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 COLLEGE OF AGRICULTURE 
 
 AGRICULTURAL EXPERIMENT STATION 
 
 BERKELEY, CALIFORNIA 
 
 PRUNING IN CALIFORNIA 
 
 By FREDERIC T. BIOLETTI 
 
 The native vine of California (Vitis California). 
 
 REVISION OP 
 
 BULLETINS Nos. 241 and 246 
 
 JUNE, 1921 
 
 UNIVERSITY OF CALIFORNIA PRESS 
 
 BERKELEY 
 
 1921
 
 DAVID P. BARROWS, President of the University. 
 
 EXPERIMENT STATION STAFF 
 
 HEADS OF DIVISIONS 
 
 THOMAS FORSYTH HUNT, Dean. 
 EDWARD J. WICKSON, Horticulture (Emeritus). 
 WALTER MULFORD, Forestry, Director of Resident Instruction. 
 CLARENCE M. HARINQ, Veterinary Science, Director Agricultural Experiment 
 Station. 
 
 B. H. CROCHERON, Director of Agricultural Extension. 
 HUBERT E. VAN NORMAN, Vice-Director, Dairy Management. 
 
 JAMES T. BARRETT, Acting Director of Citrus Experiment Station, Plant 
 
 Pathology. 
 
 WILLIAM A. SETCHELL, Botany. 
 MYER E. JAFFA, Nutrition. 
 RALPH E. SMITH, Plant Pathology. 
 JOHN W. GILMORE, Agronomy. 
 CHARLES F. SHAW, Soil Technology. 
 JOHN W. GREGG, Landscape Gardening and Floriculture. 
 FREDERIC T. BIOLETTI, Viticulture and Fruit Products. 
 WARREN T. CLARKE, Agricultural Extension. 
 JOHN S. BURD, Agricultural Chemistry. 
 CHARLES B. LIPMAN, Soil Chemistry and Bacteriology. 
 ERNEST B. BABCOCK, Genetics. 
 GORDON H. TRUE, Animal Husbandry. 
 FRITZ W. WOLL, Animal Nutrition. 
 W. P. KELLEY, Agricultural Chemistry. 
 H. J. QUAYLE, Entomology. 
 ELWOOD MEAD, Rural Institutions. 
 H. S. REED, Plant Physiology. 
 J. C. WHITTEN, Pomology. 
 FRANK ADAMS, Irrigation Investigations. 
 
 C. L. ROADHOUSE, Dairy Industry. 
 R. L. ADAMS, Farm Management. 
 
 F. L. GRIFFIN, Agricultural Education. 
 JOHN E. DOUGHERTY, Poultry Husbandry. 
 W. B. HERMS, Entomology and Parasitology. 
 L. J. FLETCHER, Agricultural Engineering. 
 EDWIN C. VOORHIES, Assistant to the Dean. 
 
 F. T. BIOLETTI L. O. BONNET 
 
 W. V. CRUESS G. BAROVETTO 
 
 A. W. CHRISTIE 
 
 * In cooperation with office of Public Roads and Rural Engineering, U. S. Department of 
 Agriculture.
 
 CONTENTS 
 
 A. INTRODUCTION 
 
 PAGE 
 
 Literature: Need of the Bulletin 5 
 
 Definition: Objects; Scope 5-6 
 
 Some Results of Defective Pruning 6 
 
 B. HABITS AND CHARACTERISTICS OP THE VINE 
 
 Vitis Vinifera: Structure of a Cultivated Vine 9 
 
 Pruning and Descriptive Terms 11 
 
 Roots; Trunk; Head; Branches; Arms; Spurs; Fruit Canes; Buds; 
 
 Shoots; Water-sprouts; Suckers; Laterals; Fruit Wood; Sterile Wood. 
 
 C. THE PRINCIPLES OF PRUNING 
 
 Physiological Principles 25 
 
 Winter Pruning _ 26 
 
 Season; Amount; Young and Old Vines; Units of Pruning. 
 
 Summer Pruning 34 
 
 Weakening effect; Concentrating effect; Uses; Disbudding; Thinning 
 of Shoots; Topping Young Vines; Suckering; Water-sprouting; Pinch- 
 ing; Topping; Defoliating; Thinning the Fruit; Ringing; Cutting 
 Surface Roots. 
 
 Restriction and Treatment of Wounds 44 
 
 Supports: Staking, Trellising 47-50 
 
 Pruning Tools: Disposal of Prunings 51 
 
 Principles of Economy 53 
 
 D. THE PRACTICE OF PRUNING 
 
 Pruning Systems: Ideals of Pruning; Calif ornian Systems 55 
 
 Periods of Development: Before Planting; Planting 64-68 
 
 First Season: First Winter Pruning; Staking 69-71 
 
 Second Season: Summer Pruning; Second Winter Pruning 72-74 
 
 Third Season: Summer Pruning; Third Winter Pruning 79-80 
 
 Pruning after the Third Winter 84 
 
 Fan-shaped Vines and Long Pruning; Double-headed Vines 89-91 
 
 Vertical Fruit Canes; Bowed Fruit Canes 93 
 
 Vertical Cordons: Single; Double; Multiple 95 
 
 Horizontal Cordons: Unilateral; Bilateral 97 
 
 Renovation of Imperfect and Misshapen Vines 103 
 
 Choice of System: List of Varieties for Long, Half-long, and Short Pruning 106
 
 ILLUSTRATIONS 
 
 Fig. 41 
 
 Cover Cut, Wild Vine of California (Viti* Fig. 39. 
 
 Calif ornica) . 
 
 Fig. 1. Trunks of V. Californica. Fig. 40. 
 
 Fig. 2. Root crown of four-year-old vine. 
 
 Fig. 3. Typical cultivated vine with short 
 arms. 
 
 Fig. 4. Typical cultivated vine with long 
 
 arms. 
 
 Fig. 5. Vine "eye," cross section. 
 Fig. 6. Fruit bud, cross section. 
 Fig. 7. Fruit bud, longitudinal section. 
 Fig. 8. Sterile bud, longitudinal section. 
 Fig. 9. Shoot showing position of blossom 
 
 bunches. 
 
 Fig. 10. Shoot showing laterals and second 
 
 crop. Fig. 49. 
 
 Fig. 11. Unit of short pruning. 
 
 Fig. 12. Unit of long pruning. 
 
 Fig. 13. Tokay bunch before and after thin- 
 ning. 
 
 Fig. 14. Black Morocco bunch improved by 
 thinning. 
 
 Fig. 15. "Cincturing" knife for ringing. 
 
 Fig. 16. Fungous decay due to large prun- 
 ing wounds. 
 
 Fig. 17. Position of pruning shears. 
 
 Fig. 18. Method of cutting the end of a 
 spur. 
 
 Fig. 19. Pruning tools. 
 
 Fig. 20. Burning the "brush" after prun- 
 ing. 
 
 Fig. 21. Brush burner. 
 
 Fig. 22. Forms of head pruning, spurs and 
 half-long. 
 
 Fig. 23. Forms of head pruning, long fruit 
 
 canes. 
 Fig. 24. Trellised vine with fan-shaped head 
 
 and long fruit canes. 
 Fig. 25. Single vertical cordon. 
 Fig. 26. Unilateral horizontal cordon. 
 Fig. 27. Forms of cutting. 
 Fig. 28. Bundle of one-year rooted vines. 
 Fig. 29. Rooted vine with single cane. 
 Fig. 30. Rooted vine with two canes. Fig. 66. 
 
 Fig. 31. Rooted vine with canes at two Fig. 67. 
 
 levels. 
 
 Fig. 32. Rooted vine pruned ready for Fig. 68. 
 
 planting. 
 Fig. 33. Ro-trd vine with roots at different Fig. 69. 
 
 levels. 
 
 Fig. 34. Result of planting too deep. Fig. 70. 
 
 Fig. 35. Root growth of a properly pruned 
 
 and properly planted young vine. Fig. 71. 
 
 Fig. 36. Growth of vine during the first 
 
 summer. Fig. 72, 
 
 Fig. 37. Vine at end of first growing season. 
 Fig. 38. Growth and treatment during the Fi &- 73 
 
 second growing season. Fig. 74. 
 
 Fig. 
 Fig. 
 Fig. 
 Fig. 
 
 Fig. 
 
 Fig. 
 Fig. 
 
 Fig. 
 Fig. 
 
 Fig. 
 Fig. 
 
 Fig. 
 Fig. 
 Fig. 
 
 Fig. 
 Fig. 
 Fig. 
 
 Fig. 
 Fig. 
 
 Fig. 
 Fig. 
 
 Fig. 65, 
 
 Second winter pruning for head 
 of medium height. 
 
 Second winter pruning for high 
 head. 
 
 Second winter pruning of very 
 vigorous vine. 
 
 Third spring, ready for disbudding. 
 
 Third spring, cane too short. 
 
 Vineyard during the third summer. 
 
 Crop at the end of the third season. 
 
 Three-year-old vine ready for prun- 
 ing. 
 
 Three-year-old vine pruned. 
 
 Three-year-old vines pruned: A, for 
 vase-formed; B, for fan-shaped 
 head. 
 
 Four-year-old vine pruned for vase- 
 formed head. 
 
 Four-year-old vine with high head. 
 
 Seven-year-old vine with fully de- 
 veloped vase-formed head. 
 
 Nine-year-old vine with fully de- 
 veloped vase-formed head pruned. 
 
 Fifteen-year-old vineyard. 
 
 Four-year-old fan-shaped vine be- 
 fore pruning. 
 
 Four-year-old fan-shaped vine after 
 pruning. 
 
 Trellised vineyard of Sultanina de- 
 fective. 
 
 Trellised Sultanina vine in full 
 bearing. 
 
 Double-headed vine on trellis. 
 
 Vine with vertical canes. 
 
 Vineyard with vertical fruit canes 
 defective. 
 
 Vertical cordon, young vine un- 
 pruned. 
 
 Vertical cordon, young vine 
 
 pruned. 
 
 Vineyard of vertical cordons. 
 
 Vertical cordon, ultimate form un- 
 pruned. 
 
 Vertical cordon, ultimate form 
 pruned. 
 
 Vertical cordon with double trunk. 
 
 Forming the cordon, second winter 
 pruning. 
 
 Half-long pruning of horizontal 
 cordons. 
 
 Horizontal cordon, unilateral, short 
 pruned. 
 
 Horizontal "cordon, unilateral, long 
 pruned, defective. 
 
 Vineyard of horizontal cordons, un- 
 ilateral, defective. 
 
 Vineyard of horizontal cordons, bi- 
 lateral. 
 
 Young vine with imperfect top. 
 
 Pruning to renew imperfect top.
 
 VINE PRUNING IN CALIFORNIA 
 
 BY FREDERIC T. BIOLETTI 
 
 PART I 
 
 INTRODUCTION 
 
 Literature. A large number of books have been published on the 
 pruning of the vine, but none of them are very well adapted to the 
 needs of the Californian vine grower. Most publications in English 
 refer to methods suited to the eastern states and to eastern varieties 
 or to the conditions of hothouse cultivation. Foreign publications, 
 besides being more or less inaccessible, refer to conditions different 
 from those of the Pacific Slope or treat the subject so broadly that the 
 grower is at a loss to choose from such a mass of material. 
 
 Need of the Bulletin. The demand for information on vine prun- 
 ing is large and the need for such information is made evident by the 
 unsightly, defective, and unprofitable condition of many of our vine- 
 yards. This seems a suitable time for the publication of a new bulletin 
 which will incorporate the experience of the older and more skillful 
 grape growers and the results of the experiments and observations of 
 the experiment station workers. The constant influx of new settlers, 
 who are planting and growing vines with little knowledge of the 
 methods which have proved best in California, and the opening up of 
 new vine-growing districts make necessary some guide that will help 
 to avoid the numerous mistakes made in the past. 
 
 Definition. The term pruning, both by derivation and usage, is 
 applied to various operations performed in cutting off certain portions 
 of the vine. There are other operations, however, the purpose of which 
 is similar or identical, which must logically and for convenience be 
 discussed at the same time. Some of these are the removal of buds and 
 shoots by other means than cutting, and the attachment of the vine 
 or its parts to stakes, wires, or other supports. For this reason some 
 writers call the subject the "pruning and training of the vine." The 
 word ' ' training, ' ' however, is misleading when applied to any of the 
 vineyard operations used in California. It implies methods of shaping 
 the vine which we do not use, and it does not properly describe the 
 various operations of suckering, disbudding, water-sprouting, and the 
 attachment of fruit canes which we do use. The word pruning, more- 
 over, seems sufficient alone, as all the other operations follow and are 
 necessitated by the methods of cutting or pruning-proper adopted. 
 
 Objects. The main objects of pruning, in the wider sense, are first, 
 to give the vine a suitable form and to conserve this form ; and second,
 
 6 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 to so regulate the bearing that the maximum quality and quantity of 
 crop may be obtained for a long series of years at the minimum expense. 
 
 Scope. The crop possibilities of a vineyard, both as regards quan- 
 tity and quality, depend on many factors, of which the chief are the 
 character of soil and climate, the amount of available water, and the 
 nature of the variety of vine. What part of these possibilities is 
 realized depends on the operations of the vineyardist on how he 
 handles the soil and the vine. One of the most important of these 
 operations is pruning. By improper pruning we may neutralize the 
 most favorable conditions and destroy the effect of the most careful 
 cultivation. The skillful pruner, on the other hand, gives his vines the 
 opportunity to utilize to the full all the natural and cultural advan- 
 tages. Many vineyards produce less than half their proper average 
 crop owing to mistakes in pruning, and there are few vineyards in the 
 state where both the amount and the quality of the crop could not be 
 increased considerably by improved methods of pruning. 
 
 There are two great difficulties in the way of reforming the pruning 
 methods in most vineyards. One is the difficulty of obtaining pruners 
 possessed of the necessary skill and knowledge. The other is the lack 
 of the proper knowledge on the part of the owner of the vineyard. 
 Of these difficulties, the latter is by far the more serious in its effects 
 and its removal would in most cases obviate the greater part of the 
 trouble resulting from the former. 
 
 Some Results of Defective Pruning. In order to emphasize the 
 necessity for proper pruning, it may be well to consider some of the 
 results of defective pruning as shown below : 
 
 1. Deficient average annual amount of crop due to: 
 
 (a) Delay of bearing of young vines. 
 
 (&) Irregularity of development of vines. 
 
 (c) Failure to utilize properly full vigor of best vines. 
 
 (d) Lack of sufficient fruit buds. 
 
 2. Inferior quality due to : 
 
 (a) Overbearing of weak vines. 
 
 (&) Irregular distribution of the grapes and consequent irreg- 
 ular ripening, 
 (c) Injurious contact of grapes with soil, canes, and each other. 
 
 3. High cost of vineyard operations, such as: 
 
 (a) Cultivation, plowing, hoeing. 
 
 (&) Pruning, suckering. 
 
 (c) Control of diseases, oidium, vine-hopper. 
 
 (d) Gathering, trimming, sorting, culling.
 
 BULLETIN 241-246 VINE PRUNING IN CALIFORNIA 7 
 
 4. Shorter life of vines due to: 
 
 (a) Pruning and cultivation wounds. 
 (6) Occasional overbearing. 
 (c) Growth of suckers. 
 
 A young vine under average conditions in California should bear 
 a paying crop at three years; that is, in the autumn of the third leaf 
 or third summer in the field. At four years it should be practically 
 in full bearing. Under exceptionally favorable conditions, bearing 
 may be nearly a year earlier than this. In the cooler regions and with 
 certain varieties, a year longer may be necessary. These results can 
 be obtained only when the pruning during the first years is properly 
 done. 
 
 Irregularity of development of individual vines is incompatible 
 with the highest returns for the whole vineyard. Vines dwarfed by 
 defective pruning can not compete with their more vigorous neighbors 
 and will fail to produce a full crop. Full returns from a vineyard 
 can be obtained only when there is comparative uniformity of vigor 
 in the individual vines. This uniformity can be secured only by care- 
 fully adapting the pruning to each case. If vigorous and weak young 
 vines are pruned alike, the former may bear nothing and increase their 
 vigor while the latter may bear worthless grapes and increase their 
 weakness. 
 
 When the vines reach the age of full bearing, the failure to adapt 
 the pruning to the individual case is equally disastrous. A method 
 of pruning adapted to a weak vine would prevent a vigorous vine from 
 bearing and waste its possibilities, while a method adapted to a vigor- 
 ous vine would cause a weak vine to attempt to bear a large crop of 
 worthless grapes and perhaps die in the 'attempt. 
 
 Certain methods of pruning may result in an abnormally large 
 crop one year, though usually at the cost of quality. Such a crop is 
 always followed by a small one. Alternate bearing of this kind dimin- 
 ishes the average crop of a term of years. The neglected possibilities 
 of one year can be utilized by the vine only in part during the follow- 
 ing year. 
 
 Unless the pruner can distinguish the fruit buds he may fail to 
 leave a sufficient number. The loss from this cause is the greater the 
 more vigorous the vines, and greater with certain varieties than with 
 others. 
 
 Bad pruning is a frequent cause of inferior quality. When the 
 crop is too large for the vigor of the vine, or even of a part of the vine, 
 the grapes will be small, will fail to develop sugar, flavor, or color and 
 may dry up or sunburn before they are ripe. Bad pruning results
 
 8 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 in uneven and improper distribution of the grapes on a vine. This is 
 particularly harmful to shipping grapes, and results in uneven ripen- 
 ing and coloring. The grapes are subjected to different conditions of 
 light and heat according to their distance from the ground and to the 
 degree in which they are shaded by the leaves or other grapes. 
 
 On a vine of unsuitable form, the bunches may lie on the ground 
 and be contaminated by the soil and subject to mildew and mold, or 
 they may be entangled with each other or with the canes, making it 
 impossible to harvest them without injury or loss. 
 
 Not only is the crop diminished and the quality injured by bad 
 pruning but the cost of production is increased. 
 
 Vines of proper and uniform shape can be plowed, cultivated, and 
 hoed with a minimum of labor. Such vines can be pruned and suck- 
 ered at much less cost than- irregular, misshapen vines. The control 
 of the vine-hopper, of oidium, and of other diseases is more difficult 
 unless the vines are of regular, standard shape. 
 
 The harvesting of the grapes, especially of shipping grapes, is much 
 simpler and more satisfactory if the vines are well pruned. The cost 
 of trimming and the loss in culls are much diminished and the ship- 
 ping qualities of the grapes improved by proper pruning. 
 
 Finally, the useful length of life of the vineyard depends to a great 
 extent on the pruning. Bad pruning not only results in large pruning 
 wounds in vital parts but exposes the vine to serious mechanical in- 
 juries from the implements of cultivation. These wounds and injuries 
 afford means of ingress to injurious parasites, borers of various kinds, 
 and particularly to infection by black knot and wood-rot fungi. Irreg- 
 ularity of bearing, also, not only makes the vine more susceptible to 
 attacks of this kind but occasional excessive crops may actually kill 
 vines. Certain mistakes in pruning favor the growth of suckers, which 
 appropriate the sap and cause drying up and final death of the crown 
 and trunk. 
 
 HABIT AND CHARACTERISTICS OF THE VINE 
 Vitis vimfera. "With a few unimportant exceptions, all the vines 
 grown for their fruit in California are varieties of Vitis vinifera, a 
 plant originating apparently in the region south of the Caucasus but 
 now growing wild throughout Western Asia and the Mediterranean 
 countries and cultivated wherever the climate is suitable. 
 
 It is sometimes called the European vine because grown in Europe 
 more largely than elsewhere, though many of our most valuable vari- 
 eties originated in Asia and Northern Africa. The varieties are some- 
 times spoken of as Californian grapes because they are not grown east 
 of the Rockies or to any great extent in North America outside of
 
 BULLETIN 241-246 V INE PRUNING IN CALIFORNIA 9 
 
 California. They include all the varieties of vines grown in California 
 except resistant stocks and a few Labrusca or eastern varieties, such 
 as Concord and Pierce, which are grown to a limited extent. This 
 difference of species between the varieties grown in the eastern states 
 and in California accounts to some extent for the differences in methods 
 of pruning, though the difference of climate is an equal if not more 
 important factor. 
 
 Vitis vinifera and its varieties, like all true vines, are sarmentose 
 plants, that is, they possess naturally long, slender, flexible trunks in- 
 capable of self-support, which attach themselves by means of tendrils 
 to trees or other available support. If allowed to grow without re- 
 striction, they will grow to the top of high trees in a manner similar 
 to the Vitis Labrusca of the eastern states or the ViUs Calif ornica of 
 the Pacific states. (See cover cut and Fig. 1.) 
 
 In vineyards, the natural habit of the vine is modified to a remark- 
 able extent, principally by pruning. Most cultivated vinifera vines 
 are given the form of a low self-supporting shrub with a short, rigid, 
 vertical trunk. This complete change of natural form is accomplished 
 without noticeable injury to the vigor or productive capacity of the 
 plant. In some cases, however, it may be carried too far and certain 
 varieties require to be allowed to develop in a somewhat more natural 
 direction. 
 
 Structure of a Cultivated Vine. The cultivated vine has a perma- 
 nent framework, consisting of root, trunk, and arms, producing an 
 annual growth of shoots, leaves, and fruit above ground, and of root- 
 lets below. 
 
 The root and its branches extend in all directions through the soil 
 wherever they find favorable conditions. Their extent is limited only 
 by the competition of other roots or by mechanical obstructions. Their 
 functions are to collect water and nutrient salts from the soil. 
 
 The trunk is usually vertical, but may be in part horizontal. It 
 varies in length from one to two feet in low and from three to six feet 
 in high vines. Its functions are the conduction and storage of food 
 materials and the support of leaves and fruit. 
 
 The arms are the smaller divisions of the framework attached to 
 the trunk. They vary in length from a few inches to a maximum of 
 about eighteen inches. They may rise radially from the top of the 
 trunk (vase form) or along its whole length (vertical cordon]. They 
 may be in one vertical plane at the top of the trunk (fan-shape) or* 
 along the whole length of the trunk (horizontal cordon). Their func- 
 tions are the production of young wood and the proper distribution of 
 leaves and fruit.
 
 10 
 
 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 The young wood produced each year by the arms is utilized to form 
 the spurs and canes which bear the leaves and fruit. Its total length 
 
 will vary in different cases from a few dozen feet to several hundred. 
 In mature vines from 90 per cent to 98 per cent of all the growth is 
 removed at each pruning.
 
 BULLETIN 241-246 yiNE PRUNING IN CALIFORNIA 11 
 
 In order to discuss pruning intelligently, it is necessary to agree on 
 the definition of the technical terms used. The terms and definitions 
 employed here are in nearly all cases those used by the majority of 
 Californian grape growers. An attempt has been made to have them 
 correspond as nearly as- possible to the terms used in other countries 
 and in the pruning of other plants. The main difficulty in this respect 
 has been with the terms spur, sucker, water-sprout, and lateral. In 
 these eases the usage of the majority of Californian grape growers has 
 been followed. 
 
 TERMS EEFEREING TO THE FORM AND STRUCTURE OF A CULTIVATED 
 
 VINE 
 
 SUBTERRANEAN PARTS 
 
 Root Tips. The extreme ends of the rootlets. 
 
 Rootlets. The finest roots, the growth of one season. (Fibrous roots.) 
 
 Root Branches. All the divisions and subdivisions of the main roots 
 older than one season. 
 
 Main Roots. The main root branches arising from the underground 
 stem or tap root. 
 
 Tap Root. A single plunging main root or prolongation of the under- 
 ground stem. 
 
 Root Crown. The base of the underground stem or region from which 
 originate the main roots. 
 
 Underground Stem. The part of the trunk below ground from the 
 bottom of which start the main roots or tap root. 
 
 AERIAL PARTS. (A) SKELETON OP FRAMEWORK AFTER PRUNING 
 Trunk or Stem. The unbranched body of the vine. 
 Head or Crown. The top of the trunk or region from which arise the 
 
 arms or branches. 
 Branches. The main division (when long) of the trunk. Branches 
 
 bear arms. 
 Arms. The main divisions (when short) of the trunk or branches. 
 
 Arms bear spurs. 
 
 Spurs. Short pieces of the bases of canes, 1 to 4 nodes with their eyes. 
 Fruit Spurs. Spurs left for the production of fruit. 
 Wood Spurs, (a) Renewal Spurs. Spurs left to supply fruit spurs, 
 or fruit canes for the following year, 1 to 2 eyes. 
 
 ( b ) Replacing Spurs. Spurs left to supply growth for the replac- 
 ing of defective arms, 1 eye. 
 Fruit Canes. Canes left for fruit, iy 2 to 6 feet long.
 
 12 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 AERIAL PARTS. (B) ANNUAL GROWTH 
 
 1. Before the formation of leaves 
 Eyes. The compound buds on the canes. 
 
 Fruit Buds. Buds from which a shoot, bearing flowers, will be pro- 
 duced. 
 
 Wood Buds. Buds from which sterile shoots will be produced. 
 
 Base Bud. The lowest well formed eye at the base of a cane or spur. 
 
 Latent Buds. Buds which have remained dormant for one growing 
 season or more. 
 
 Adventitious Buds. Buds arising from leafless parts of the wood. 
 
 Main Buds. The large central buds of the eyes. 
 
 Secondary Buds. The small lateral buds of the eyes. 
 
 2. During the formation of leaves 
 Shoots. The succulent growth arising from a bud. 
 Fruit Shoots. Shoots bearing flowers. 
 
 Sterile Shoots. Shoots not bearing flowers. 
 
 Water-sprouts. Shoots arising from dormant or adventitious buds. 
 Suckers. Shoots originating below the surface of the ground. 
 Laterals. Secondary shoots arising from buds in the axils of the 
 leaves of the main shoots. 
 
 3. After the fall of the leaves, before pruning 
 
 Old Wood. Parts of the vine older than one year. 
 
 Canes. Young wood or growth of the current season, consisting of a 
 series of nodes, each furnished with an eye and separated by the 
 smooth portions called internodes. 
 
 Fruit Wood. Canes with fruit buds, usually growing out of two-year- 
 old wood. 
 
 Sterile Wood. Canes without fruit buds. Those growing out of wood 
 older than two years are usually unfruitful. 
 
 Roots. The pruner has little to do with the roots except when 
 planting or in cases where it is advisable to remove certain roots of 
 young vines, either because they arise from the scion above the union 
 or because they are too near the surface. Regular root pruning at 
 intervals of several years is practiced in some regions, but there seems 
 to be no sufficient reason for the practice in California. Some of the 
 pruner 's operations on the above-ground portions of the vine, however, 
 may promote or restrict root growth.
 
 BULLETIN 241-246 VINE PRUNING IN CALIFORNIA 13 
 
 Every year the vine makes a new growth of rootlets, and these root- 
 lets are its sole means of obtaining water and soil nutrients. These it 
 absorbs by means of the young cells and root hairs within an inch or 
 two of the root tips. The rest of the root system serves to conduct the 
 absorbed material to the aerial parts of the vine, to store reserve 
 material for spring growth, and to hold the vine in place. The posi- 
 tion, number, and vigor of the roots depend more on the nature of the 
 soil and cultural operations than on anything the pruner can do. 
 
 The amount of root growth and that of top growth are mutually 
 dependent. Conditions or methods which stimulate one stimulate the 
 other and we can not curtail one without diminishing the other. The 
 position of the root system is due partly to the nature of the variety or 
 species of vine and partly to the conditions of penetrability, moisture, 
 aeration, and food supply of the soil. The roots will go where the con- 
 ditions are most favorable, and nothing we can do that does not change 
 these conditions will affect the position of the roots except temporarily. 
 The rootlets of a vine grown from a short cutting will finally occupy 
 exactly the same position in the soil as those of a vine grown from a 
 long cutting. 
 
 We can, to some extent, influence the position of the main roots by 
 appropriate treatment of the vine when young. No main roots should 
 arise nearer than four or five inches from the surface or they will be 
 in danger of injury from the plow. The danger of shallow rooting is 
 greatest in irrigated soils, and can be avoided by infrequent and deep 
 irrigations, by avoiding a continually wet surface in the growing season 
 during the first two years, and, when necessary, by removing the sur- 
 face roots while they are small. 
 
 The best root system is that in which all the main roots arise from 
 the root crown at the bottom of the underground stem. This does not 
 prevent the utilization of soil at higher levels, for rootlets will grow 
 into all regions of the soil where the conditions are favorable, whether 
 below or above the main roots. No injury need be apprehended from 
 the plowing up of small rootlets, as they will reform as fast as needed. 
 The destruction of a main root, however, is harmful, as it not only 
 destroys all the rootlets by means of which the root was feeding the 
 vine but the large wound may allow decay organisms to attack the vine. 
 
 The supposed superiority of a tap root is a mere superstition, except 
 in so far as it involves a perfect continuity of healthy tissue from 
 trunk to root branches. Two, three, or more main roots from the root 
 crown are equally effective, providing there are no unhealed wounds 
 on the underground stem to be attacked by boring insects or decay 
 fungi. (See Fig. 2.)
 
 14 
 
 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 In wet soils there is usually a definite root crown at 6 to 8 inches 
 below the surface. The planting of a long "cutting will not alter this 
 condition, as the roots simply start where the moisture, temperature, 
 
 Fig. 2. Boot crown of a four-year-old vine. 
 
 and aeration are most favorable, and all below this point dies. In 
 drier soils a short cutting will make a similar root crown, but on a 
 longer cutting the main roots may arise at various levels. There is no 
 objection to the latter form of branching, providing some roots start 
 at the bottom of the cutting and completely heal the surface. A root 
 crown at the surface of the ground is very objectionable, as it is very
 
 BULLETIN 241-246 V INE PRUNING IN CALIFORNIA 15 
 
 subject to injury from plow and hoe, and consequently subject to 
 infection by black knot and wood rot fungi. It also makes clean culti- 
 vation and the perfect and economical removal of suckers difficult. A 
 clean, smooth, healthy underground stem of at least six inches is very 
 desirable. 
 
 The Trunk. The trunk is the body, we might almost say the life, 
 of the vine. Its main functions are to support the bearing wood at 
 the right height from the ground, to carry water and nutrient salts 
 from the roots to the leaves and elaborated food from the leaves to the 
 roots. On its continued healthy state depend the vigor, crop, and long 
 life of the whole vine. It is a continuation of the underground stem 
 and should be perfectly straight, smooth, and without wound, branch, 
 or cane from the ground to the head. Its length or height depends 
 on the variety, climate, and form of pruning, but should in all cases 
 be sufficient to allow of close cultivation, easy hoeing, and proper 
 suckering. This means a minimum of about ten inches. Except in 
 certain forms of trellis and cordon pruning, it should never exceed 
 thirty inches. A greater height is expensive to develop and sustain, 
 and gives no corresponding advantage. 
 
 The trunk is formed during the first three years of the life of 
 the vine. Defects acquired during this period can never be wholly 
 remedied. 
 
 The Head of the vine is the top of the trunk or region from which 
 the arms start. At first it is more or less indefinite, the spurs from 
 which the arms finally develop being at heights varying six, eight, or 
 more inches, but none nearer than six inches, from the surface of the 
 ground. As the vine develops the arms are gradually brought to prac- 
 tically the same level by the removal of ill-placed arms before they 
 become large, and a definite head is thus formed at the desired height. 
 
 Branches or long major divisions of the trunk are not used in any 
 of the forms of pruning adopted in California. Their only use is for 
 certain forms of high trellises or for covering an arbor. "Where the 
 trunk is simply elongated without branching or has only two horizontal 
 branches at the same level, the form is called a cordon. In these forms 
 there is no proper head or crown. 
 
 The Arms are the final divisions of the body of the vine and bear 
 the spurs and fruit canes. They should be long enough to spread the 
 crop so as to give all the bunches the necessary sun, space, and air to 
 develop properly. They should not be long enough to interfere with 
 cultivation nor to be in danger from the use of implements. The more 
 vigorous the vine and the higher the trunk, the longer the arms should 
 be. The correct length will vary from six to eighteen inches.
 
 16 
 
 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 The arras constantly tend to become too long, and it requires skill, 
 knowledge, and foresight on the part of the primer to keep them within 
 the required limits. Long arms tend to become weak and unfruitful 
 and must periodically be replaced by new arms developed from as near 
 the head of the vine as possible. 
 
 Fig. 3. Carignane vine fifteen years old. Well formed trunk, head and 
 arms; short spurs. 
 
 The number of the arms will depend on the style of pruning 
 adopted and on the size of the vine. With very short pruning, the 
 number on a mature vine will vary from three or four on a small 
 growing variety in poor soil to ten or fifteen with very vigorous vines. 
 With longer pruning, the number of arms is correspondingly decreased, 
 and with long or cane pruning, two to four arms are all that should 
 be given. 
 
 The arrangement of the arms depends principally on the planting 
 plan and method of cultivation. When the vines are approximately 
 equidistant in both directions and cross-cultivation is practiced, the 
 arms should be arranged as symmetrically as possible in ' ' vase-form. ' '
 
 BULLETIN 241-246 yiNE PRUNING IN CALIFORNIA 17 
 
 When the vines are planted closer together in rows with wider "ave- 
 nues" between them, especially when trellised, cross-cultivation is im- 
 possible. In these cases it is of great importance that the arms should 
 be "fan-shaped," that is, arranged in a single plane. This makes it 
 possible to plow and cultivate very close to the vine and even to cut 
 out some of the ridge between the vines with horse hoes or cultivators. 
 Care in shaping the young vines properly in this respect will obviate 
 a great deal of expensive hand hoeing when the vines are large. The 
 formation of the arms takes place principally during the third and 
 fourth years, and mistakes made at this time can be remedied only 
 imperfectly later and then at the cost of mutilating the vine. Trellised 
 vineyards carelessly pruned in this respect often have a strip two feet 
 wide along each row to be worked by hand. This strip can be reduced 
 to six inches or less by carefully forming the vines when young. 
 
 At and near the ends of each arm are left pieces of young wood 
 called Spurs or Fruit Canes, according to their length. The spurs 
 vary in length according to their purpose. In ordinary short pruning 
 most of the spurs are expected to produce fruit. Only fruit wood, 
 that is, canes growing out of two-year-old wood, therefore, should as 
 a rule be used for this purpose. The average length of a fruit spur 
 is two nodes, which will give three eyes counting the base bud situated 
 at the base of the cane or separated only by a very short node, which is 
 not counted. Fruit spurs will vary in length, however, from one node 
 to four, according, principally, to the vigor and size of the cane. The 
 larger the cane the more eyes are left on the spur it furnishes. 
 
 A Renewal Spur is not left primarily for fruit. Its purpose is to 
 furnish shoots from which the fruit spurs and fruit canes are formed 
 the following year. In ordinary short pruning, the fruit spurs func- 
 tion at the same time as renewal spurs. In long pruning, one or two 
 renewal spurs must be left below each fruit cane to supply fruit canes 
 for the following year. Such spurs usually consist of two full inter- 
 nodes, but in some cases they may be reduced to a single node with two 
 eyes, including the base bud. As renewal spurs are not intended for 
 fruit, only a sufficient number should be left to insure enough properly 
 placed canes for the next pruning. This number will be the same as 
 the number of fruit canes with one, two, or three extra per vine to 
 provide against the failure of some and, when necessary, for an in- 
 creased number of fruit canes the following year. Sterile or fruit 
 wood may be used for this purpose, as either will produce fruit wood 
 for the following year. 
 
 The function of a Replacing Spur is to provide for the shortening 
 or replacing of an over-elongated or otherwise defective arm. It con-
 
 18 
 
 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION 
 
 sists of only one internode and its eye, or even of simply the base bud, 
 if this is well formed. As it is intended to replace an arm, it is chosen 
 as near the base of this arm as is practicable without necessitating too 
 large a wound when the arm is removed. Unless the arm is very de- 
 fective, its removal is deferred until the year following that in which 
 the replacing spur is left. In this way no crop is sacrificed. The first 
 year the crop is borne as usual on spurs or canes at the end of the arm. 
 The next year the replacing spur has produced fruit wood from which 
 
 Fig. 4. Muscat vine, over fifteen years old. Trunk too short, arms too long, 
 but head of good form. 
 
 can be formed a fruit spur which in turn develops into a new arm. 
 A replacing spur consists always of sterile wood, as it is made from a 
 cane growing out of old wood near the base of the arm. Replacing of 
 arms should be done with sufficient frequency to avoid making the 
 very large wounds that would be necessary if the arms were allowed 
 to become very old and large. Spurs intended to produce new arms 
 on developing young vines are left longer and usually consist of fruit 
 wood, as they function as fruit spurs at the same time. 
 
 Some varieties of vines will not bear satisfactory crops on spurs, 
 owing to the sterility of the buds near the base of the cane or to the 
 small size of the bunches, which makes it difficult to obtain a sufficient
 
 BULLETIN 241-246 
 
 VINE PRUNING IN CALIFORNIA 
 
 19 
 
 number from spurs to constitute a full crop. In such cases it is neces- 
 sary to adopt some form of long pruning, with fruit canes. A fruit 
 cane is a piece of the current year's fruit wood from one and one-half 
 to six feet long. These canes should be taken, wherever possible, from 
 canes growing out of two-year-old wood, in order to increase the proba- 
 bility of the buds being fruitful. Fruit buds may occur on water- 
 sprouts more or less abundantly, according to the variety, age, and 
 condition of the vine, but are nearly always much more abundant on 
 "fruit wood." Canes less than two feet long are not advisable, as 
 they are difficult to attach to the stake or trellis without breaking. 
 No advantage, on the other hand, is obained from fruit canes longer 
 
 Fig. 5. Cross-section through vine 
 two or three lateral secondary buds. 
 
 : eye" showing central main bud and 
 
 than six feet. Fruit canes six feet long will produce as many fruiting 
 shoots as the vine can develop properly. Longer canes, indeed, usually 
 fail to develop any more fruit, as a larger proportion of the buds fail 
 to start, and even when more start the fruit is apt to be inferior in 
 size and quality. Four six-foot fruit canes with five or six renewal 
 spurs is about the maximum for the strongest vines with our methods 
 of planting. More than this may sometimes increase the crop, but 
 nearly always at the expense of quality and often with great danger 
 of injurying the vine by over-bearing. This latter danger is particu- 
 larly to be feared with vines grafted on resistant stock. 
 
 The buds on the canes are usually called Eyes by the pruner. This 
 is a convenient term, as they are more than simple buds, and consist 
 of a main central bud with one or two smaller secondary buds within 
 the same bud scales. (See Fig. 5.)
 
 20 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 The external appearance of all the eyes on a vine is similar. They 
 differ, however, in the important respect that some are capable of 
 producing a fruit-bearing shoot and others are not. The former are 
 called Fruit Buds, the latter sterile or Wood Buds. If a thin section 
 of a bud is examined under a low-power microscope, it is possible to 
 determine its character. The embryo blossom bunches can be seen in 
 the fruit buds. ( See Figs. 5, 6. ) 
 
 There is no external difference in appearance between fruitful and 
 sterile buds, and the pruner has no means of determining with cer- 
 tainty whether an eye contains the possibility of fruiting or not. He 
 can, however, tell what the relative probability of fruitfulness is with 
 
 Fig. 6. Cross-section through fruit bud showing two embryonic blossom 
 bunches. 
 
 different eyes, which, for this purpose, is all that is necessary. This 
 he determines by the position of the eye relative to the cane and the 
 vine. The greatest probability of fruitfulness occurs in the eyes of 
 canes which have been produced by the spurs of the previous year. 
 Or, as the pruner expresses it, the fruit buds are on the canes growing 
 out of two-year-old wood. Canes produced by older wood, that is, 
 which have grown from dormant or adventitious buds, are usually 
 sterile. 
 
 The position of the eye on the cane is also of importance in judging 
 its probability of fruitfulness. The base bud is usually sterile. The 
 first and second eyes are usually fruitful with most vinifera varieties. 
 With some varieties the probability of fruitfulness is not great until 
 we reach the fourth or fifth eye. Beyond this point the eyes are 
 usually fruitful until we reach a point where the cane is imperfectly
 
 BULLETIN 241-246 V INE PRUNING IN CALIFORNIA 21 
 
 developed or badly matured. Sterility of the lower buds makes long 
 pruning necessary. 
 
 A bud may be fruitful in varying degrees. A thoroughly fruitful 
 bud of most vinif era varieties will produce, on the average, two bunches 
 
 Fig. 7. Longitudinal section of a fruit bud showing an embryonic shoot 
 with embryonic leaves and blossom bunch. 
 
 of grapes of full normal size. The number may be one, two, or three, 
 according to variety. A less fruitful bud will produce fewer and 
 smaller bunches. This reduction of fruitfulness may continue until 
 
 Fig. 8. Longitudinal section of a sterile bud. 
 
 we find buds producing bunches which are little more than tendrils 
 with a few grapes. Such buds are practically sterile, producing few 
 blossoms or grapes. Their bunches are easily distinguished from the 
 loose bunches due to the dropping of the blossoms without setting.
 
 22 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION 
 
 Wood Buds are those which contain no rudiments of blossoms and 
 are therefore incapable of yielding fruit. They are distinguished by 
 their position, which can be inferred from what has been said regarding 
 the position of fruit buds. They occur principally on water-sprouts, 
 and include usually also base, dormant, and adventitious buds. 
 
 Some of the buds left on a vine do not develop the first year, or 
 produce only a few small leaves. Such cases are particularly frequent 
 in long pruning. These buds will often develop the second year, 
 especially if shorter pruning is adopted. These buds are called dor- 
 mant or latent buds, and are usually sterile. 
 
 "With the warm weather of spring the bud commences to swell, then 
 to elongate, and finally produces a growing shoot, which pushes through 
 the bud scales. This shoot is produced by the main bud. If the vine 
 is vigorous and the number of buds limited, one or both of the secondary 
 buds may start and produce smaller shoots. An injury to the main 
 bud results in the starting of the secondary buds. Cut worms or other 
 gnawing insects often kill the main bud without injurying the others. 
 The same effect may be produced by a moderate frost after the shoots 
 have started. A heavy spring frost will sometimes kill all the buds in 
 a started eye. 
 
 The main buds on fruit wood usually produce fruit-bearing shoots. 
 The rudimentary blossom bunches can be seen after the shoot has 
 grown a few inches. There are usually two, or more rarely one or 
 three. They may occur at the second and third, the third and fourth, 
 or the fourth and fifth nodes. ( See Fig. 9. ) Shoots from the second- 
 ary buds may also produce fruit, but the bunches are smaller and less 
 numerous. 
 
 A shoot coming from a dormant or adventitious bud on the old 
 wood is called a water-sprout, and is usually sterile. A sucker is a 
 shoot coming from below the ground. On vines which are properly 
 handled the suckers are removed carefully and completely every year, 
 so that few are produced, and as these must come from adventitious 
 buds they are sterile. If the removal of suckers is neglected or im- 
 perfect, a shoot below ground may arise from the base of a sucker of 
 the previous year, in which case it may be fruitful. 
 
 As a shoot grows it produces one leaf at each node on alternate 
 sides. Opposite the second, third, fourth, or fifth leaf is produced a 
 blossom bunch on fruit shoots and a tendril on sterile shoots. The 
 next one or two nodes may also produce bunches or tendrils. As the 
 shoot elongates further it produces more tendrils, but not at all nodes 
 in vinifera varieties. Every third node is usually without a tendril.
 
 BULLETIN 241-246 
 
 VINE PRUNING IN CALIFORNIA 
 
 23 
 
 In the axil of the leaf, that is, in the angle between the leaf stalk 
 and the shoot, occurs a bud. Beside this bud very often arises a side 
 shoot called a lateral. These laterals may be short or may grow long 
 and form large lateral canes. Any injury to the growing tip of the 
 main shoot stimulates the production and growth of laterals. Laterals 
 
 Fig. 9. Blossom-bearing shoot of Tokay vine. 
 
 of some varieties may produce fruit like main canes. This fruit is the 
 so-called second crop, and is usually about two weeks later than the 
 main crop. Rarely these laterals may produce secondary laterals in 
 their turn, which in a few varieties may produce a third crop. (See 
 Fig. 10.) 
 
 We have on a vine, therefore, fruit wood and sterile wood, but this 
 distinction is not absolute. Some of the buds on the fruit wood may
 
 24 
 
 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION 
 
 be sterile, while some on the sterile wood may be fruitful. The proba- 
 bilities of fruitfulness, however, are so much greater in one case than 
 in the other that the pruner may safely proceed as though it were 
 absolute. Moreover, with proper pruning little sterile wood is pro- 
 duced. The difference between the two kinds of wood varies greatly 
 with different varieties. On a Muscat of Alexandria most of the buds, 
 
 Fig. 10. Fruit-bearing cane of Black Morocco, showing (I) first crop, (II) 
 second crop, and (III) third crop. 
 
 even on water-sprout canes, contain rudiments of blossoms. The fruit- 
 fulness of all kinds of wood, moreover, depends on weather, soil, and 
 cultural conditions. In some cases the conditons are so favorable to 
 fruitfulness that even the water-sprouts bear. Hot summers, certain 
 mechanical injuries to the vine, and grafting on certain stocks have a 
 tendency to increase the proportion of fruit buds on all kinds of canes. 
 On the other hand, cool summers, excessive growth of vine due to over- 
 abundance of water, or nitrogen in the soil may cause buds in all 
 positions to be mostly sterile.
 
 BULLETIN 241-246 VINE PRUNING IN CALIFORNIA 25 
 
 THE PRINCIPLES OF PRUNING 
 
 Physiological Principles. The correct pruning of the vine is based 
 on certain facts regarding plant growth and nutrition which the pruner 
 should understand. Some of these facts apply to all plants; others 
 are peculiar to the vine. 
 
 1. The vine prepares its food by means of the green coloring matter 
 (chlorophyll) of its leaves. All the sugar, starch, and other substances 
 which make up the body of the vine, and those of its crop, are elabor- 
 ated in the leaves by means of the chlorophyll under the influence of 
 sunlight. Carbon dioxide from the air and water from the soil furnish 
 the main bulk, while the mineral salts from the soil furnish a smaller 
 but equally necessary part. A certain area of green leaf surface func- 
 tioning for a certain time is necessary to produce sufficient nourishment 
 for the vital needs of the vine and for the production of the crop. 
 Those leaves most exposed to the direct rays of the sun are most active 
 in absorbing and producing food. The youngest leaves take all their 
 nourishment from the older parts of the plant ; somewhat older leaves 
 use up more nutrient material than they absorb from the air. A 
 young shoot may thus be looked on as, in a sense, parasitic upon the 
 rest of the vine. After a certain stage, the leaves produce more food 
 material than they utilize, and the excess goes to support other parts. 
 The true feeders of the vine and of its crop, therefore, are the mature, 
 dark green leaves. 
 
 This principle shows that any method which forces an unnecessary 
 growth of young shoots or removes mature leaves, while still active, 
 limits the possibilities of production both of wood and of fruit. 
 
 2. Within certain limits the tendency to fruitfulness of a vine or 
 a part of a vine is inversely proportionate to its vegetative vigor. 
 Within these limits, methods which increase the vegetative vigor dimin- 
 ish bearing, and, vice versa, methods which diminish vigor increase 
 bearing. Failure to reckon with this fact and to maintain a proper 
 mean between the two extremes leads, on the one hand, to comparative 
 sterility and, on the other, to over-bearing and premature exhaustion 
 of the vine. 
 
 The correct treatment of a vine is that which invigorates it as much 
 as is possible without diminishing the crop. 
 
 3. Other conditions being equal, an excess of foliage is accompanied 
 by a small amount of fruit, an excess of fruit by diminished foliage. 
 This and No. 4 are corollaries of Principle No. 2. 
 
 4. Bending, twisting, or otherwise injurying the tissues of the vines 
 or of its parts tend to diminish its vegetative vigor and, therefore, 
 unless excessive, to increase its fruitfulness.
 
 26 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 5. The vine tends to force out terminal buds and to expend most 
 of its energy on the shoots farthest from the trunk. To keep the vine 
 within practical limits, this tendency must be controlled by the re- 
 moval of terminal buds or by measures which check the flow of sap 
 and force the growth of buds nearer the stock. 
 
 Certain defective styles of pruning fail to recognize this tendency, 
 and are therefore impracticable and can not be continued indefinitely. 
 One of the commonest of these is the tying of fruit canes vertically to 
 a stake. 
 
 6. The nearer a shoot or cane approaches the vertical the more 
 vigorous it will be. 
 
 This principle is made use of in the Guyot and similar systems of 
 pruning. The shoots from renewal spurs are tied up vertically to a 
 stake and are thus rendered vigorous. On the other hand, the fruit 
 canes are tied horizontally to wires, thus moderating the vigor and 
 increasing fruitfulness. 
 
 7. The size of vines or parts of vines is inversely as their number, 
 if other conditons remain the same. 
 
 Thus the fewer vines to the acre the larger each will grow; the 
 fewer shoots allowed to grow on a vine or the arm of a vine the larger 
 each individual shoot. This principle extends to the fruit. If we want 
 large bunches, we must limit their number ; if we want large berries, 
 there must not be too many on a bunch. 
 
 Winter Pruning. The principal pruning of the vine is done while 
 the plant is dormant, between the fall of the leaves at the beginning 
 of winter and the starting of the buds at the beginning of spring. In 
 large vineyards it may be necessary to spread the pruning over most 
 of this period ; in smaller vineyards it is usually possible to prune in 
 the month which is judged most favorable. 
 
 Season. In deciding on the best time for pruning we must con- 
 sider the convenience of other cultural operations and the effect of the 
 period on the health and bearing of the vine. 
 
 For convenience, the earlier the pruning is done the better. Prun- 
 ing in November or December gives abundant time to gather and to 
 remove the prunings, to apply fertilizers, to plow, irrigate, and sucker 
 and to tie up the fruit canes before the starting of the buds. 
 
 The effects of the time of pruning on the vigor and fruitfulness of 
 the vine bear a close relation to the location and amount of reserve 
 food material in the various parts of the plant. 
 
 During the summer the leaves feed the canes, trunk, and roots. 
 Just before the natural fall of the leaves the canes contain the maxi- 
 mum amount of food material, viz., starch, sugar, cellulose, and other
 
 BULLETIN 241-246 VINE PRUNING IN CALIFORNIA 27 
 
 carbohydrates. For two or three weeks, immediately following the 
 fall of the leaves, much of these substances passes rapidly doAvnwards 
 to accumulate as reserves in the roots. Later, these reserves ascend 
 again slowly, to supply the above-ground portions of the vine which, 
 though dormant, still require nutrition. In spring, during the period 
 just before and just after the starting of the buds, this upward migra- 
 tion of reserves is more rapid and continues until the young leaves are 
 sufficiently developed to supply the vine with its carbohydrate food. 1 
 
 If we prune a vine, therefore, immediately after the fall of the 
 leaves, the cuttings contain the largest amount of reserves and are in 
 the best condition for use in grafting or planting. Three or four weeks 
 later, the roots contain the largest amount of reserves, and if pruning 
 is done then, they will be in the best condition to promote a vigorous 
 growth in the spring. When the buds start in the spring, the root has 
 lost some of its reserves, which have been used up by the canes during 
 the winter. Pruning at this time, therefore, results in a less vigorous 
 growth of shoots, but also, usually, in a better "setting" of the crop. 
 
 The effects of the time of pruning on the vigor and crop of the vine 
 have been investigated by Professor Ravaz 2 in a series of experiments 
 extending over seven years, with results which have been in the main 
 corroborated by tests at the University Farm. 
 
 Vines pruned immediately after the fall of the leaves were the 
 earliest to start in the spring. Those pruned when the vines were most 
 dormant (end of December and beginning of January) started, on the 
 average, four days later. Those pruned at the time pruned vines 
 commence to bleed (about February 20 in the south of France) started 
 about six days later. Pruning when the terminal buds commenced to 
 swell (March) retarded the lower buds eleven days, and where the 
 terminal buds had grown two or three inches, twenty days. 
 
 The starting of the buds was late, therefore, in proportion to the 
 lateness of the pruning. One exception, however, was noticed. Vines 
 pruned soon after the vintage and while still covered with green leaves 
 started, on the average, ten days later than those pruned after the fall 
 of the leaves. 
 
 The retardation of the starting of the shoots in the spring may be 
 a valuable means of escaping the injurious effects of spring frosts. In 
 one of our tests, the crop on nine rows pruned March 13 w r as saved, 
 while that of twelve rows pruned November 19 and December 21 was 
 completely ruined by a frost on April 21. Late pruning also retards 
 
 1 Vidal, J. L., "Les reserves de la vigne, " Eevue de Viticulture, I, 895 to 
 903. 
 
 2Eavaz, L., "Taille hative ou taille tardive," 1912.
 
 28 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION 
 
 the blossoming, though to a less degree than it does the starting. Prun- 
 ing as late as March may retard the blossoming ten days. The time 
 of ripening is also influenced slightly in the same direction. When 
 spring frosts occur, this influence appears to be reversed. The vines 
 pruned early may blossom and ripen their fruit later. This is because, 
 the frost having destroyed the first shoots, the only flowers and fruit 
 that appear are on buds which have started after the frost. 
 
 Vines pruned before the fall of the leaves are weakened. Other- 
 wise the time of winter pruning has little direct effect on the vigor of 
 the vines. Professor Ravaz notes somewhat greater vigor in vines 
 pruned earliest in the dormant season. On these vines the crop was 
 diminished by frost. The extra vigor was due, therefore, probably not 
 to the time of pruning but to the lack of crop. 
 
 Late pruned vines gave on the average larger crops. Professor 
 Ravaz accounts for this by their escape from frost. The later blos- 
 soming, which increases the probability of warm dry weather for 
 pollination, may also be a factor. At the University Farm Muscat 
 vines pruned in the middle of April produced 22.6 pounds per vine, 
 while vines pruned in December produced only 10.1 pounds, with no 
 injury from frost in either case. 
 
 Pruning may be done, therefore, in frostless locations and with 
 varieties which set their fruit well at any time when the vines are 
 without leaves. Where spring frosts are common, the pruning should 
 be as near the time of the swelling of the buds as possible. The bene- 
 fits of late pruning without its inconveniences may be obtained by the 
 system of "double" or ''clean" pruning practiced in some regions. 
 This may be applied in various ways. The simplest is to shear off all 
 the canes to a length of 15 to 18 inches at any convenient time during 
 the winter. This permits plowing and other cultural operations, and 
 the final pruning is done in April. A better method is to prune the 
 vines as usual but to leave the spurs with four or five extra buds. 
 These spurs are then shortened back to the proper length as late as 
 practicable. In some cases the method practiced in the Medoc may be 
 used. This consists in leaving a foot or fifteen inches of cane beyond 
 the last bud needed and removing all the extra buds at the time of 
 pruning. The starting of the base buds is retarded by a piece of cane 
 above them whether this piece of cane has buds or not. 
 
 Early pruning (December) promotes the vigor of the vine and 
 results in early starting of the buds. Late pruning (March, April) 
 promotes fruiting, may slightly weaken the vines, and results in late 
 starting of the buds. Weak vines, those which have borne too much 
 Or which have been injured by insects or diseases, are better pruned
 
 BULLETIN 241-246 yiNE PRUNING IN CALIFORNIA 29 
 
 early. Very vigorous vines, especially in frosty locations, should be 
 pruned late. 
 
 Amount of Pruwing. An average vine before pruning may have 
 twenty-five canes, with an average of fifteen buds on each, or three 
 hundred and seventy-five buds in all. If the vine is not pruned, all 
 these buds will not start or produce shoots. Probably not more than 
 fifty or one hundred will do so. If we prune the canes back so that 
 we leave only fifty or one hundred buds, the same number of shoots 
 will be produced. The only effect will be that buds nearer the bases 
 of the canes will start instead of buds near the ends. ( See Physiolog- 
 ical Principal No. 5, p. 26). The quality and quantity of the crop and 
 the vigor of the vine and its shoots will be influenced little if at all. 
 
 If we prune the vine more severely and leave only half this number 
 of buds, a smaller number of shoots will be produced. As this smaller 
 number has the same store of reserve material in trunk and root to 
 draw on and the same root system to supply water and soil nutrients, 
 each shoot will grow larger and more vigorously. See Principle No. 7, 
 p. 26.) This smaller number of large shoots will produce approxi- 
 mately as much foliage as the larger number of small shoots on the 
 unpruned vine, and the vigor of the vine is therefore not perceptibly 
 diminished. 
 
 There will also be a smaller number of bunches produced, but each 
 of these will be larger and have larger berries, so that the total weight 
 of the crop will be as large as on an unpruned vine. In fact, the 
 weight of crop will probably be larger, as it is easier for the vine to 
 supply the water and sugar which constitute the main bulk of large 
 berries than the stems, seeds, and skins which form a larger part of 
 small berries. 
 
 "We can increase the severity of the pruning, that is, dimmish the 
 number of buds left, still further, without materially influencing either 
 the vigor of the vine, the amount of foliage, or the weight of crop. 
 Beyond a certain point, however, the crop is diminished. There are 
 two reasons for this. One is that there is a certain maximum size for 
 the bunches and berries of any particular vine. When we have reached 
 this maximum, any further decrease of fruit bunches results in a 
 diminished crop. The other is that the excessive vigor given to the 
 shoots is unfavorable to fruiting (see Physiological Principle No. 2, 
 p. 25), often causing "coulure" or dropping of the blossoms without 
 "setting." The pruner should endeavor, therefore, to leave just 
 enough fruit buds to furnish the number of bunches that the vine 
 can bring to perfection.
 
 30 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 Beyond this point the crop is diminished and the vigor of the vine 
 correspondingly increased. This increase of vigor is not the direct 
 effect of the pruning, but of the curtailment of the crop, which frees 
 a larger part of the energies of the vine for the work of growth and 
 the building up of tissues and reserves. It seems highly probable that 
 the direct effect of the pruning is really weakening, and that, if the 
 only object were growth and vigor, it could be accomplished better by 
 removing the blossoms in the spring and doing no pruning in the 
 winter. The weakening effect, however, of even the heaviest pruning 
 is probably much less than with most woody plants because the vine 
 produces shoots from dormant and adventitious buds with so much 
 facility, and the amount of growth and foliage than can be developed 
 by sterile shoots in a single year is so great. 
 
 Heavy winter pruning, therefore, invigorates the vine by dimin- 
 ishing the crop. Light winter pruning increases the crop. If this 
 increase is represented by a larger number of bunches than the vine 
 can properly nourish, the crop will be inferior in quality and the vine 
 weakened by over-bearing. On a mature vine of normal vigor, the 
 pruner should leave the same number of spurs and fruit buds as was 
 left the year before. If the vine appears abnormally vigorous, more 
 fruit buds should be left in order to utilize this vigor in the production 
 of crop. On the other hand, if the vine appears weak, it should be 
 pruned more severely than the previous year, that is, fewer fruit buds 
 should be left, in order to strengthen the vine by diverting its activities 
 from crop production to building up tissues and replenishing its store 
 of reserve food materials. Any attempt to make a weak vine bear a 
 large crop can result only in further weakening of the vine and in 
 the production of inferior grapes. By pruning such a vine for a small 
 crop the grapes obtained will be of good quality and the vine invigor- 
 ated so that it can produce normal crops in subsequent years. 
 
 These arguments apply not only to individual vines but to indi- 
 vidual arms or canes of a vine. The number of fruit canes, spurs, or 
 buds should be in proportion to the strength of the arm. A fruit 
 cane or fruit spur should be longer the more vigorous it is. 
 
 The vigor of a vine is determined not only by the growth it has 
 made but by the amount of reserves contained in its canes and body. 
 Its condition in this respect can be determined by an inspection of 
 the canes. These should be firm and heavy. Soft, pithy canes indicate 
 weakness, and should never be left for fruit canes. If all or most of 
 the canes on a vine are of this character, the vine should be pruned 
 very short ; in extreme cases, sufficiently short to prevent any attempt 
 to bear. On the other hand, long, firm canes should be made to pro- 
 duce fruit by being left longer whether as fruit spurs or fruit canes.
 
 BULLETIN 241-246 V INE PRUNING IN CALIFORNIA 31 
 
 The iodine test is useful in determining the condition of canes or 
 vines in respect to reserves. For this test a solution of iodine in 75 
 per cent alcohol is used, 100 parts of alcohol to one part of iodine, by 
 weight. A clean, slanting cut is made through the cane and a few 
 drops of the solution placed on the cut. In three to five minutes a 
 well nourished cane, containing abundance of starch (reserves), turns 
 black all over the cut. An imperfectly nourished cane will turn black 
 only on the medullary rays, which will show like the spokes of a wheel. 
 If only a few black specks are produced by the iodine, reserves are 
 lacking. In the first case the canes are good for use as cuttings or 
 grafts and indicate that the vine is capable of producing a good crop. 
 The pruning should be correspondingly generous. In the last case 
 the cuttings are useless and the vine should be pruned very short. A 
 few tests of this kind in a vineyard will give a fair idea of the amount 
 of reserves in the vines, and such a test is a valuable aid in determining 
 the amount of pruning to give. 
 
 Young and Old Vines. During the first part of the life of the vine 
 the main, if not the only, object of the pruner is to develop a frame- 
 work of proper form. The methods of doing this and the time re- 
 quired will depend on the form aimed at and on the more or less favor- 
 able conditions for rapid growth. The crop during this formative 
 period should be a secondary object. In fact, nothing is lost if it is 
 left out of consideration altogether, except in so far as it affects the 
 attainment of the desired form. Vines which are pruned so as to 
 reach most rapidly and perfectly a desirable shape will not only bear 
 more when they reach adult size but will practically always bear more 
 fruit during the formative period than if the fruit alone were in view. 
 
 In pruning an adult vine, two objects must be kept in view : first, 
 the production of the crop of the current year, and second, the mainte- 
 nance of the proper form of the vine. Each of these objects is perhaps 
 of equal importance. On the attainment of the first depends the 
 current crop, on that of the second all future crops. 
 
 Units of Pruning. "When a vine has reached the stage of full 
 bearing, pruning consists in leaving certain parts of the new wood 
 for fruiting, other parts for renewal or the production of wood for the 
 next year, and finally other parts for the replacing or shortening of 
 arms. All new wood not needed for these purposes and all arms to 
 be replaced are removed. 
 
 Whatever the system of pruning adopted, in all our California!! 
 systems each arm of each vine is treated by the same method, modified 
 only by the vigor of the individual cane, arm, or vine. There are two 
 general methods used, viz., spur pruning and cane pruning. The
 
 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 treatment of a single arm by either of these methods may be called 
 the "unit of pruning." 
 
 The unit of pruning in spur pruning is illustrated in Fig. 11, 
 representing a long arm about seven years old. At the end of the arm 
 is shown the two-eye spur ($ 2 ) of the previous year bearing two canes 
 ( C and C l ) . Near the base of the arm is shown a single water-sprout 
 (W$) growing out of old wood. Such an arm would normally bear 
 other canes, but as they would all be removed entirely at pruning they 
 are omitted to simplify the figure. 
 
 In pruning such an arm, one of the canes growing out of the spur 
 of the previous year (8 2 ) is cut back to form a new spur and the other 
 removed entirely. In deciding on which cane to use for the new spur, 
 
 Fig. 11. Unit of short pruning. 
 
 we must choose one that is suitable for fruiting, viz., well ripened, of 
 moderate thickness, and with well formed buds. Of those which fulfill 
 this condition, we must choose that which is in the best position to 
 preserve the form of the vine. This, in most cases, will be the lowest 
 (C in the figure), because it increases the length of the arm the least. 
 If the lowest, however, is weak, broken, or otherwise unsuitable, we 
 are obliged to take one higher up. 
 
 When a cane arising from the base bud of the spur of the previous 
 year is chosen for the new spur, the length of the arm is lengthened 
 imperceptibly. A spur from the first bud (C) will lengthen it usually 
 little over an inch, one from the second bud (C) three or four inches. 
 In any case, the arm finally becomes too long, like the one in the figure. 
 It must then be shortened or replaced. This can be done by using a 
 conveniently placed water-sprout for a replacing spur, as at R in the 
 figure, and cutting back the arm in the place indicated by the line g.
 
 BULLETIN 241-246 
 
 VINE PRUNING IN CALIFORNIA 
 
 33 
 
 This cutting back of an arm should be deferred until the following 
 year, as the replacing spur will produce little or no fruit. In the mean- 
 time the fruit spur from cane C will bear a crop and the replacing 
 spur R will produce fruit wood for the following year. 
 
 The cane chosen (C) is cut at a, b, or d, leaving a fruit spur of 
 one, two, or three fruit buds and the cane, C\, removed entirely by a 
 cut at /. The more vigorous the variety and the particular cane the 
 more buds should be left. The water-sprout is cut back at a, leaving a 
 replacing spur of one eye. Of course, a replacing spur is left only in 
 case the arm is too long and will require shortening the next year. 
 
 Fig. 12. Unit of long pruning. 
 
 The unit in short pruning consists then of a single fruit spur of 
 one, two, or three fruit buds. 
 
 The unit of pruning in long and half long systems is shown in 
 Fig. 12, and consists of a fruit cane, F 2 , with its renewal spur, 8^ 
 
 In the illustration, S 2 represents the renewal spur of two years 
 previous. On it was left a fruit cane, F 2 , which has produced the crop 
 of the previous season, and a renewal spur, 8 19 which has produced 
 fruit wood for the present season. 
 
 In pruning, the fruit cane F 2 is removed entirely at g. The upper 
 cane, C, of the renewal spur, $ t , is used for a new fruit cane and 
 shortened to about / for half long and to about f 1 for long priming. 
 The lower cane, C 1 , is cut back at a to form a renewal spur, S, which 
 will produce the new wood for the next winter pruning.
 
 34 i UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 This is the normal method of procedure, but various modifications 
 are often necessary. If the cane, C, is unsuitable on account of lack 
 of vigor, other canes such as C lt or even B, D, near the base of the old 
 fruit cane, may be used for a new fruit cane. The essential point is 
 that the cane used for this purpose shall originate from two-year-old 
 wood. In the same way any suitably placed cane may be used for a 
 renewal spur. Water-sprouts from three-year, four-year, or older wood 
 may also be used (RP). The essential point in this case is that the 
 renewal spur shall be below the fruit cane, that is, nearer the trunk. 
 
 Replacing spurs for shortening the arms are occasionally needed, 
 as in spur pruning, but usually the same spur can be used both for 
 renewal and replacing. The water-sprout, RP, may be used for this 
 purpose, cutting it at h or 6, according to its vigor. 
 
 Slimmer or Herbaceous Pruning. Summer pruning, of which there 
 are many forms, consists in the removal of buds, shoots, or leaves while 
 they are green or herbaceous, and is done therefore while the vine is 
 growing or active. 
 
 The effects of summer pruning are in some respects very different 
 from those of winter pruning and in some quite the opposite. If we 
 remove a part of a cane in the winter, we do not weaken the vine at 
 all ; in fact, we may strengthen it indirectly by diminishing bearing. 
 If we remove a growing cane in the summer, on the contrary, we 
 weaken the vine because we remove leaves, which are its principal 
 feeding organs and to which it owes its vigor. (See Principle No. 1, 
 p. 25.) 
 
 This weakening effect is greatest in the middle of summer when 
 the vine is most active and most in need of the food supplied by the 
 leaves. 
 
 The removal of all the leaves by defoliating insects at this time may 
 kill the vine. The danger is not so great early in the spring, when we 
 can remove a certain number of small shoots without serious injury. 
 In fact, vines struck by spring frosts are often more vigorous the fol- 
 lowing year, because the weakness due to removal of leaves is more 
 than counterbalanced by the strengthening due to lack of crop. It is 
 least harmful late in the autumn after the canes have matured and the 
 leaves have begun to turn yellow. 
 
 The removal of growing shoots or parts of shoots also has an effect 
 similar to that of winter pruning, viz., the concentration of the growth 
 of the vine on the parts which remain. This concentrating effect and 
 the weakening effect occur in inverse ratio and vary according to the 
 time and method of operation. In early spring, at the starting of the 
 shoots, the weakening effect is very slight and the concentrating effect
 
 BULLETIN 241-246 yiNE PRUNING IN CALIFORNIA 35 
 
 almost as marked as that of winter pruning. In early summer, with 
 the vines in full growth, the weakening effect may be sufficient to com- 
 pletely neutralize the concentrating effect, i.e., the removal of some 
 of the shoots may so weaken the vine that there will be no increase of 
 growth in those which are left. Still later, the weakening effect may 
 exceed the concentrating effect, i.e., the shoots which are left will make 
 less growth than if none had been removed. 
 
 Uses of Summer Pruning. Summer pruning has various uses, of 
 which the principal are : 
 
 1. To direct the growth into useful parts of the vine : disbudding, 
 thinning of shoots, and topping of young vines; suckering; water- 
 sprouting. 
 
 2. To moderate the vigor of the vine and so increase its bearing : 
 pinching, topping. 
 
 3. To increase the size of fruit (at expense of sweetness) : topping. 
 
 4. To increase the shade on the fruit: topping or pinching to pro- 
 mote upright position of shoots and growth of laterals. 
 
 5. To decrease the shade on the fruit : defoliating. 
 
 Three other operations performed in the summer may be considered 
 as forms of summer pruning, viz. : 
 
 6. Thinning of the fruit. 
 
 7. Ringing. 
 
 8. Removal of scion and surface roots. 
 
 Disbudding is practiced on young vines during the second and third 
 years. It consists in removing the buds from the lower part of the 
 stem of the vine in order to concentrate the growth in the shoots above 
 and to avoid the production of canes low down where they would have 
 to be cut off later. The buds are not removed until they have grown 
 an inch or two. Many of them are dormant or adventitious and the 
 attempt to remove them earlier would make it necessary to go over the 
 vineyard too often. The sooner they are removed, however, the better, 
 before they have used up much of the reserves of the vine and when the 
 concentrating effect of their removal is at its maximum. On younger 
 vines which have not yet formed a stem, it consists in removing all the 
 buds but one in order to concentrate all the growth ino a single shoot, 
 from which the following year the stem will be formed. 
 
 Thinning of Shoots. The purpose of this operation is the same as 
 that of disbudding. It is done after the shoots have grown several 
 inches or more. It is inferior to early disbudding, as it is more weak- 
 ening to the vine and the concentrating effect is correspondingly less. 
 It is simpler than disbudding, as it necessitates going over the vine- 
 yard only once. It is used principally during the second year for vines
 
 36 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION 
 
 which have been cut back to two buds at the end of the first season's 
 growth. 
 
 Topping the Young Vines. When by disbudding or thinning of 
 shoots during the second year all the growth has been concentrated 
 into a single shoot this shoot will grow with great vigor. When it has 
 grown about twelve inches above the top of the stake, that is, above the 
 height at which it is intended to develop the head, it should be topped. 
 This topping has the effect of forcing the growth of laterals. These 
 laterals may be used at the following winter pruning as fruit spurs 
 and as the commencement of permanent arms. If this topping is not 
 done, there may be very few buds on the cane when mature at the 
 height at which it is desired to make a head. It will, therefore, be 
 difficult to find buds in the proper place for the development of the 
 arms and to produce the crop of grapes which the vine should yield the 
 third year. 
 
 During the third summer the number of shoots will be small for 
 the vigor of the young vine. They will grow rapidly and be very 
 liable to be broken off by the wind while tender and succulent. If 
 topped before they are long enough to afford sufficient leverage to the 
 force of the wind, they will have time to lignify their tissues and be- 
 come tough enough to withstand the pressure of the wind. Topping 
 at this time helps to keep the shoots upright and makes it easier to 
 give the arms the proper direction at the following winter pruning. 
 
 Suckering. This is the removal of all shoots which originate at or 
 below the surface of the ground. Neglect of suckering results in 
 diminished vigor of the whole above-ground portion of the vine. The 
 suckers bear little or no fruit, hence grow vigorously and appropriate 
 the sap 'which should nourish the whole vine. Finally, the top may 
 die, the whole growth go into the suckers, and all the benefits of a 
 properly shaped vine will be lost. Such a vine can be renovated only 
 by cutting off the old stump and building up a new vine from a vigor- 
 ous sucker. 
 
 With grafted vines the consequences are even more serious. The 
 suckers, coming from the stock, take the sap even more easily from 
 the top, since the top is connected to the root by the grafting union, 
 and the passage of water and food materials to the top is therefore 
 impeded. A grafted vine which has been seriously weakened by the 
 prolonged growth of suckers is useless and can not be renovated. 
 
 Suckering should be done with the greatest care and thoroughness 
 during the first four or five years. This will save a great deal of 
 expensive and troublesome work later. Very few suckers will be pro- 
 duced by vines which have been properly cared for in this respect
 
 BULLETIN 241-246 yiNE PRUNING IN CALIFORNIA 37 
 
 during the first three years, and such vines will usually cease to produce 
 any after five or six years. Vines on which the suckering has been 
 imperfectly done during the first three years, on the contrary, will 
 always produce an abundant crop of underground shoots every year. 
 
 Suckering, like disbudding, should be done as early in the season 
 as possible for the reasons already given. Another and even more 
 important reason is that suckers which are removed late, and especially 
 those which are allowed to grow the whole summer, promote the for- 
 mation of dormant buds and of tissue which readily forms adventitious 
 buds below ground. 
 
 It is necessary to sucker young vines two or three times during the 
 spring. This is done every time the vines are visited for hoeing or 
 tying up. When the suckers are soft and succulent they are easily 
 pulled off without cutting. They must be removed completely from 
 the base. When they get a little tough it is necessary to dig down 
 to their point of origin for this purpose. It is worse than useless to 
 remove a sucker partially. The part which remains forms an under- 
 ground spur or arm which will be a source of perennial trouble. 
 
 Water-Sprmiting. This is the removal of sterile shoots. When it 
 is done to prevent growth in places where growth is not wanted, or to 
 concentrate growth in parts where it is wanted, it is advisable. The 
 removal of all sterile shoots in all cases, on the theory that they are 
 useless, however, is mistaken practice. 
 
 The growth of a large number of water-sprouts is usually a sign 
 that the full vigor if the vine is not being used for the production of 
 crop. The cure for this is longer, or a different style, of winter prun- 
 ing. The production of sterile shoots on what ought to be fruit wood 
 often indicates some cultural error, such as excess of water, nitrogen 
 or humus, too late growth of the vine in autumn, or excessive vigor. 
 
 Water-sprouts may be removed with good results in certain cases. 
 If the vines are weak, the growth may by this means be concentrated 
 in the bearing shoots, which will thus be able to nourish their crop 
 better. In this case the water-sprouts must be removed early, before 
 they have grown more than a few inches. Otherwise the vine will be 
 still further weakened and the trouble increased the following year. 
 If the vines are excessively vigorous, diminishing the foliage by the 
 late removal of water-sprouts may correct this defect. It is more 
 reasonable, however, to utilize this vigor for crop production by a 
 change in the winter pruning. Water-sprouts are sometimes trouble^ 
 some by growing through the bunches, making it impossible to gather 
 the crop without injury. This is particularly harmful with shipping 
 grapes. Where much of this trouble exists it indicates that the vine
 
 38 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 has an unsuitable shape. This can be modified in the winter pruning 
 by spreading the vine sufficiently to allow all the bunches to hang free. 
 
 Sterile shoots are by no means completely useless. The foliage 
 they produce nourishes the vine and makes it more capable of bearing 
 fruit. They are needed for use as renewal and replacing spurs, for 
 which purpose they are better than fruitful shoots, since they are more 
 vigorous. 
 
 Pinching. This consists of the removal of the growing tip of a 
 shoot with thumb and finger. Its weakening effect is very slight, as 
 no expanded leaves and a very small amount of material are sacrificed. 
 
 Its immediate effect is to arrest the elongation of the shoot. If 
 this is done when the shoot is 15 to 18 inches long, the shoot has time 
 to become sufficiently tough to resist the wind before it gets long 
 enough to afford the wind much pressure surface. Shoots pinched as 
 early as this usually produce a new growing tip from a lateral which 
 later can not be distinguished from an original growing tip. Later 
 pinching usually causes the growth of several strong laterals. 
 
 Pinching fruit shoots, just before blossoming, tends to make the 
 fruit "set" better. It is, therefore, a remedy for "coulure." Pinch- 
 ing the first shoots on a fruit cane tends to promote the starting of other 
 buds, and therefore the production of more bunches. By pinching 
 we can accomplish most of the objects of topping with a minimum 
 weakening effect on the vine. Fig. 9 shows a fruiting shoot at the 
 proper stage for the first pinching. 
 
 Topping Bearing Vines. This consists in removing one, two, or 
 more feet of the end of a growing shoot, usually in June or July or 
 later. In some regions topping is practiced regularly twice or even 
 three times during the season. In general, it is used more in the cooler 
 districts than in the hotter. 
 
 If practiced early, it has much the same effect as pinching. It 
 tends to keep the canes upright and to cause the development of lat- 
 erals. It involves the removal of leaves and is therefore weakening, 
 which may be an advantage with extra vigorous vines. In very windy 
 districts it is necessary to prevent the shoots from being broken off 
 by the wind. The later the topping is done the more leaves are re- 
 moved and the more weakening the practice is to the vine. Constant 
 severe topping may have a serious effect on the vigor of even the 
 strongest vines. Topping nearly always decreases the crop. Topping 
 three times at Davis diminished the crop of Tokays by 32 per cent and 
 of Carignanes by 42 per cent. 
 
 In general, moderate topping tends to increase the size of the grapes 
 and to decrease their quality. For table grapes on vigorous vines it
 
 BULLETIN 241-246 VINE PRUNING IN CALIFORNIA 39 
 
 is sometimes an advantage if not carried too far. At least three or 
 four leaves should be left above the fruit when the topping is done 
 early and seven or eight when the topping is done late. For wine or 
 raisin grapes it is seldom advisable, as it decreases the sugar and flavor 
 of the grapes. "With long pruned vines, especially when trellised, it 
 is often possible to obtain the benefits of the practice without its de- 
 fects by topping only the shoots on the fruit canes and allowing the 
 shoots on the replacing spurs to grow normally. 
 
 Both pinching and topping are used frequently with the object of 
 protecting the fruit from sunburn, by increasing the shade for the 
 grapes. For this purpose pinching is much superior to topping. 
 
 When a shoot is allowed to grow without interference it takes at 
 first a more or less upright direction. As it increases in length its 
 weight tends to bend it over to a more or less horizontal or downward 
 direction. With some rapidly elongating varieties, the shoots bend over 
 and take a reclining position, resting for a considerable portion of 
 their length on the soil. With nearly all varieties they will finally 
 bend outward and downward sufficiently to open up the center of the 
 vine to the sun. 
 
 In many cases this opening up of the center is an advantage, pro- 
 moting the coloring of the grapes and making easier the control of 
 mildew. In some it encourages sunburn of the grapes. Sunburn, 
 however, is not due alone to the direct rays of the sun, since some 
 bunches completley exposed do not sunburn and others much shaded 
 do. Sunburn occurs in vineyards where the shade temperature seldom 
 goes above 100 F. and may not occur in others where it often rises 
 to 110 F. 
 
 The commonest form of sunburn is due to an excess of evaporation 
 over sap supply. If more water is lost through the skin of the grape 
 than is supplied through the stem, it will dry up. An excess or a 
 deficiency of water in the soil may curtail the sap supply and sunburn 
 will result. Defective or diseased roots, wounds, or fungi in stems 
 or arms may have the same effect. Increasing the shade, therefore, 
 is merely a palliative, and any method which weakens the vine will 
 increase the trouble. 
 
 If we pinch the growing shoots once or twice before they are three 
 feet long, we increase the shade in two ways. First, they grow more 
 upright as they are relieved from the weight of the growing top until 
 they are sufficiently lignified to retain their upright position. Second, 
 they produce laterals which increase the number of leaves near their 
 bases and over the head of the vine. Topping, being done later, is less 
 effective in these respects, and, moreover, as it involves the removal
 
 40 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION 
 
 of feeding leaves may weaken the vine so much as to increase the 
 trouble. 
 
 Defoliating. The development of the color of the grapes is influ- 
 enced more by the light than by the heat of the sun. The coloring of 
 Tokay grapes can sometimes be facilitated in the cooler districts by 
 means which expose the bunches to more sunlight. One of these means 
 is the removal of leaves. This, of course, will tend to weaken the vine. 
 If the vines are excessively vigorous, this may not be a disadvantage. 
 If only the leaves in the center of the vine, which have already com- 
 menced to turn yellow, are removed, the weakening effect may be very 
 slight. Better insolation, however, can usually be obtained more 
 profitably by changing the form of the vine or by thinning the bunches. 
 
 Removal of the interior leaves may be useful in some cases, with 
 very late varieties, to protect them from molding after rains. It allows 
 sun and air to reach the grapes freely and helps the moisture to evap- 
 orate quickly from their surfaces. 
 
 "Sheeping" the vineyard, or allowing sheep to eat the leaves im- 
 mediately or soon after gathering the crop, is undoubtedly a bad 
 practice. It removes the leaves before they have fulfilled their im- 
 portant duty of providing the reserve food to be stored up in cane, 
 trunk, and roots for the growth of the following spring. 
 
 Thinning the Fruit. Many otherwise suitable grapes do not ship 
 well on account of the excessive compactness of the bunch. A compact 
 bunch is difficult to pack without injury and can not be freed from 
 imperfect berries without spoiling good berries. 
 
 This excessive compactness can be prevented by thinning before 
 the berries are one-third grown. Thinning, moreover, increases the 
 size of the berries, hastens ripening, promotes coloring, and lessens 
 some forms of sunburn. The practice is regularly followed with suc- 
 cess by many growers of Tokay, Black Morocco, Luglienga, and other 
 grapes, whose bunches are usually too compact. While apparently 
 costly, the expense is often more than counterbalanced by the saving 
 in trimming of the ripe grapes. The increase of quality thus becomes 
 a net gain. 
 
 The bunches are thinned at any time after the berries have set and 
 before they have reached one-third their mature diameter. No bunches 
 are removed, only a certain proportion of the berries of each bunch. 
 The number of berries to be removed will depend upon how compact 
 the unthinned bunches usually become. In general, it will vary from 
 one-third to one-half of the total number. The thinning is effected by 
 cutting out several of the side branchlets of the bunch. The branch- 
 lets should be removed principally from the part of the bunch which
 
 BULLETIN 241-246 V INE PRUNING IN CALIFORNIA 
 
 41 
 
 A B 
 
 Fig. 13. Bunch of green grapes before (A) and after (B) thinning.
 
 42 
 
 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 has most tendency to compactness, usually the upper part. The work 
 can be done very rapidly, as no great care is necessary in preserving 
 the shape of the bunch. However irregular or one-sided the bunch 
 
 Fig. 14. Black Morocco improved by thinning. 
 
 looks immediately after thinning, it will round out and become regular 
 before ripening. 
 
 A long, narrow-bladed knife or a pair of grape-trimming scissors 
 can be used conveniently for this work.
 
 BULLETIN 241-246 
 
 VINE PRUNING IN CALIFORNIA 
 
 43 
 
 Ringing. This operation, called also "cincturing" and "annular 
 incision," consists in the removal of a ring of bark from a growing 
 shoot, a cane, an arm, or the trunk. It is performed by means of a 
 special two-bladed knife (see Fig. 15) or other instrument, according 
 to the size of the part of the vine to be treated. The ring is removed 
 from a part of the vine below the fruit. This prevents the passage of 
 food material to the lower parts of the vine and causes its accumu- 
 lation in the parts above the incision. 
 
 8 
 
 Fig. 15. Cincturing knife. 
 
 The knife should not penetrate the wood and the ring of bark 
 removed should be from one-third to one-fourth of an inch in width. 
 If it is too narrow, the wound heals too quickly and the full effect of 
 the operation is not obtained ; if too wide, the part treated may die. 
 
 Ringing is used to (1) increase the size of the fruit and to hasten 
 the ripening; (2) to prevent "early coulure," the dropping of the 
 blossoms without "setting"; (3) prevent "late coulure," the dropping 
 of the small, immature berries after setting. 
 
 For the first purpose the ringing is practiced on the cane just below 
 the fruit or on the arm. It is done after the berries have set and 
 reached about one-third full size. For the second purpose it is done 
 a few days before the blossoms open, and for the third a few days after 
 the berries have set. 
 
 All forms of ringing are more or less weakening to the vine, and 
 it is seldom possible to treat the same vine in this way for several years
 
 44 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 in succession without serious injury. An exception to this is the ring- 
 ing oMhe Black Corinth in Greece and Australia, which has been prac- 
 ticed for years and has lately been tried with success in California. 
 In this case the ringing is done to the main trunk at or near the sur- 
 face of the ground and the wound is covered with soil immediately. 
 This practice produces large and regular crops on a variety which 
 usually bears hardly any crop without it. 
 
 Ringing the trunk in this way has proved much less dangerous than 
 what at first sight would seem to be a milder operation, the ringing 
 of single arms. The reason is, probably, that when the wound is pro- 
 tected by a covering of soil it heals perfectly, but when exposed as it 
 is on an arm it fails to heal or heals only in part. 
 
 Removal of Surface Roots. As has already been pointed out, the 
 final position of the feeding roots depends on the soil conditions and 
 can not be influenced by pruning. The position of the main roots can, 
 however, be modified to some extent in certain cases. 
 
 Young vines in some soils tend to start roots at or very close to the 
 surface of the ground. This is especially frequent where summer 
 irrigation is practiced. If these roots are allowed to grow, they will 
 form main roots and are liable to injury in cultivation. During the 
 first and second year, therefore, it is advisable to cut off any roots which 
 form within four or five inches of the surface. This can be done when 
 the vines are hoed and suckered. When grafted vines are planted, the 
 union is placed above the ground but is covered by "hilling" up the 
 soil. This may cause roots to start from the scion. These roots must 
 be carefully cut off before they become large or the vine will fail to 
 nourish its resistant roots. 
 
 Restriction and Treatment of Wounds. The possible length of life 
 of a vine so far as we know is unlimited. The actual profitable life 
 varies from a few years to fifty or more. Vines are sometimes killed 
 by some disease or unfavorable conditons, such as severe frosts, pro- 
 longed drought, etc. Most vines fail and become unprofitable from 
 the effects of an accumulation of small injuries. Among the chief of 
 these are pruning wounds. Wounds are not only harmful in them- 
 selves by destroying wood, bark, and other conducting tissues, but they 
 allow the entrance of boring insects and wood-destroying fungi whose 
 effects are even more destructive. 
 
 All pruning wounds, therefore, should be made as small as possible, 
 especially in the main body and other permanent parts of the vine. 
 The necessity of making large wounds can be avoided to a great extent 
 by using foresight.
 
 BULLETIN 241-246 V INE PRUNING IN CALIFORNIA 
 
 45 
 
 \ 
 
 
 Fig. 16. Spore-bearing bodies of an "oyster-shell fungus" showing fungous 
 decay of the trunk due to large pruning wounds.
 
 46 
 
 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 Useless shoots and canes should be removed while they are small 
 and young, and necessary renewals of arms or branches should be 
 made before the part to be suppressed becomes too large. Where large 
 wounds are unavoidable, they should be made as smooth as possible 
 and protected by an antiseptic swabbing with 2 per cent copper sulfate 
 solution and covered with a good white lead paint. The vine heals its 
 wounds from the inside by the production of gummy matters or thy- 
 loses which fill up the cells and tissues and so prevent loss of sap. It 
 
 Fig. 17. Proper position of pruning shears with relation to the vine when 
 making a cut. 
 
 does not cover the wounds with healing tissue from the outside with the 
 facility that many fruit trees possess. Wounds much over an inch in 
 diameter seldom heal over completely. 
 
 By careful and skillful use of the pruning tools the harm of neces- 
 sary wounds can be reduced to a minimum. 
 
 All cuts should be made clean and smooth. This requires that the 
 shears should be of good quality and kept sharp. The cuts should be 
 made in such a way that there is no splitting or cracking of the wood. 
 This is accomplished by holding the shears in the proper way at the 
 proper angle and by avoiding any undue bending of the portion of the 
 vine to be removed. Canes for spurs should be cut at a slight angle, 
 and not at a right angle to the grain. In cutting off a cane or spur
 
 BULLETIN 241-246 V INE PRUNING IN CALIFORNIA 4:1 
 
 entirely the blade of the shear should be placed against the vine and 
 should cut upwards as shown in Fig. 17. This will insure a clean, 
 close cut without splitting. Any cut on the body of the vine should 
 be made in such a way as to leave as small a wound as possible and at 
 the same time to leave no projecting stub. Stubs of dead wood prevent 
 healing over and interfere considerably with future pruning. 
 
 In spur pruning it is considered best to cut through the bud above 
 the last one that it is desired to have grow as at C in Fig. 18. This 
 leaves the woody diaphragm intact and protects the spur from injury. 
 If the spur is cut at C 1} a long piece of internode is left exposing the 
 pith. As this pith dries and shrinks it allows water to enter and forms 
 an excellent place for molds to grow which may destroy the bud below. 
 It requires some skill and practice to cut exactly in the right place ; 
 if by mistake the cut is made just below the diaphragm, the breeding 
 place for molds has its maximum size. For this reason most pruners 
 make the cut at C 2 , about half an inch above the last bud. If the 
 shears are sharp and the cut made at an angle of about 45 degrees 
 behind the bud, no injury results. 
 
 In removing a piece of old wood at the base of a spur or fruit cane 
 it is best to leave a little projecting stub. Too close cutting in this 
 case is apt to injure the spur or cane. The projecting stub can be 
 removed the following year, when the spur has grown larger, without 
 danger of injury. (See Fig. 18.) 
 
 Supports. With most systems of pruning, after the vine has 
 reached a certain stage of development and its framework is complete, 
 it will support itself after the manner of a small tree. Where the 
 trunk is elongated, as in the Cordon systems, the trunk requires a 
 permanent support. 
 
 Young vines in all systems require support for at least three or 
 four years, and usually longer. A skillful pruner can build up a low 
 vine without a support, but the results are imperfect at best and the 
 method requires so much skill and care that there is no economic gain. 
 
 In long or cane pruning there must always be some support fur- 
 nished for the fruit canes. 
 
 The supports needed then are of two kinds: (1) temporary sup- 
 ports to keep young vines in place until their trunks become large and 
 strong enough to support themselves, and (2) permanent supports for 
 long trunks or for the annual fruit canes. 
 
 Staking. As temporary supports some form of stake is always 
 used. Nearly all vine stakes in California are made of redwood, which 
 is remarkably adapted to the purpose. It is light, easy to work, and 
 very resistant to decay unless made from sap wood. Split stakes are
 
 48 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 the best, as sawn stakes may be cut diagonally across the grain and 
 many may break in driving. 
 
 Pine, spruce, poplar, willow, or any other wood may be used for 
 temporary stakes if redwood is unavailable. Most of these woods will 
 last two years, and can be made to last four or five if treated with 
 
 Fig. 18. Methods of cutting the end of a spur. 
 
 copper sulfate. Saplings and small branches can sometimes be con- 
 veniently used. These should be peeled and pointed as soon as cut 
 and then stood for twenty-four hours in a tub containing a few inches 
 of a 5 per cent solution of copper sulfate (bluestone). At the end of 
 this time the copper sulfate will have penetrated the whole stake and 
 can usually be seen at the upper end. If the saplings are allowed to 
 dry even for a few days, it will require a very much longer time to 
 impregnate them with the antiseptic.
 
 BULLETIN 241-246 
 
 VINE PRUNING IN CALIFORNIA 
 
 49 
 
 Other materials may sometimes be conveniently used for temporary 
 stakes. The commonest of these is the Spanish reed or bamboo, Arundo 
 donax, used in many places as a windbreak. These are somewhat 
 slender for the purpose and require much readjusting, but will serve 
 when better materials are not available. 
 
 The length of the stake depends principally on the height at which 
 it is desired to head the vine and on the character of the soil. It should 
 be of such length that, after being driven into the ground, sufficient 
 will be below the surface to keep it firm and prevent its being loosened 
 by the force of the wind acting on the vine tied to it, and sufficient will 
 be above the surface to extend for two inches above the height at which 
 
 Fig. 19. Pruning tools: one-hand shears; two-hand shears; curved saw. 
 
 it is intended to head the vines. Its thickness should be in proportion 
 to its height. 
 
 When redwood is used a stake thirty inches long and one and one- 
 fourth inches square will be sufficient in firm ground for small growing 
 vines like the Zinfandel. This will allow fifteen inches to be driven 
 into the ground and leave fifteen inches above, which is sufficient for 
 vines to be headed at twelve inches. If the ground is loose or sandy, 
 a slightly longer stake is advisable. For strong growing varieties such 
 as Carignane or Tokay, especially when growing in rich soil, a stake 
 two inches square and thirty-six to forty-eight inches long is necessary. 
 This will permit the heading of the vine at eighteen to thirty inches. 
 
 When a stake is used as a permanent support for fruit canes it is 
 usually made six feet long and two or two and one-quarter inches in 
 diameter. A somewhat shorter stake, four to five feet, will suffice if 
 the canes are bowed. A similar stake is needed for a vertical cordon.
 
 50 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 Trellising. A trellis consists of one, two, or rarely three wires 
 stretched horizontally along the rows. The wires are held at the ends 
 by heavy stakes or fence posts braced firmly. These wires are sup- 
 ported at intervals along the row by stakes of appropriate height. A 
 tall stake at each vine is often used for this purpose, as it serves also 
 for tying up the yearly replacing shoots. This stake, however, is ex- 
 pensive and troublesome in pruning, and is not indispensable. It is 
 usually sufficient to place stakes at intervals of two or even three vines. 
 Such stakes should be placed between the vines and need be long 
 enough only to reach to the top wire. Some growers dispense with 
 these intermediate stakes altogether. A temporary stake is used with 
 each vine until it has developed a self-supporting trunk. The single 
 wire used is then allowed to rest on the head of each vine. If the vines 
 are even and well formed, this is a convenient arrangement, as it facili- 
 tates the tightening of loose wires and the repair of those which break. 
 
 The height of the first or only wire is usually about thirty inches, 
 that of the second forty-five inches, and that of the third fifty-seven 
 inches when three are used. In many cases one wire is sufficient to 
 support the fruit canes. In windy locations the second wire is useful 
 to support the growing shoots. "With very vigorous vines the second 
 wire may be used also for fruit canes. A third wire may be used in this 
 case to support the fruit shoots, but is seldom or never really needed, 
 and adds much to the cost of both installation and maintenance. The 
 wire most used is No. 12 galvanized fencing wire. No. 10 or No. 11 is 
 a little better, as No. 12 will frequently break. When more than one 
 wire is used No. 11 for the bottom wire, which supports the weight of 
 the fruit, and No. 13 for the others is satisfactory. 
 
 For the horizontal cordon system the same method of trellising is 
 used. 
 
 For attaching the vines, canes, and shoots to stakes and trellises 
 some form of rope or string is commonly used. The balls of twine 
 used on self-binders are convenient and preferred by some. This 
 twine, however, is not quite strong enough for the main body of the 
 vine, especially in windy locations, unless doubled, though it is ex- 
 cellent for tying fruit canes to stake or trellis. A similar but heavier 
 material called grape-twine is excellent. Old ropes, such as discarded 
 ship cables, can sometimes be obtained cheaply, and, if cut into suit- 
 able lengths, the single strands are easily separated and form very good 
 tying material. 
 
 It is false economy to use material for tying of insufficient strength 
 or durability. It results 'in much troublesome extra work in retying 
 or in defective vines.
 
 BULLETIN 241-246 
 
 VINE PRUNING IN CALIFORNIA 
 
 51 
 
 In the hands of very careful workmen, nothing is better than wire 
 for tying up young vines at the winter pruning. It holds the vine 
 permanently and securely. Used carelessly, however, it may cut the 
 bark, and unless discretion is used in the placing of the tie and care in 
 its removal when necessary the vines may be girdled and killed. The 
 wire from hay bales is suitable for this purpose, though it is unneces- 
 sarily heavy. No. 16 galvanized fencing wire is of about the right 
 weight. 
 
 Other materials used are raffia for the fruit canes and osier willows 
 for the body of the vine. Raffia is unreliable in strength and inferior 
 for this purpose to binding twine. Nothing is better than osier willow 
 to attach the trunk of a young vine to the stake, but it is rarely obtain- 
 able and requires some special skill to use. 
 
 Fig. 20. Burning the brush in the vineyard after pruning. 
 
 Pruning Tools. The best tool for pruning vines is a pair of shears 
 of the Swiss form (see Fig. 19). If vines are properly pruned every 
 year, it will seldom be necessary to make cuts too large for these shears, 
 except when arms have to be replaced or last year's fruit canes 
 removed. For this purpose a curved saw should be carried by the 
 pruner. For vines which make a very heavy growth or which have 
 been unskillfully pruned a pair of two-handed pruning shears similar 
 to those used for tree pruning may be used. If these are of good form, 
 kept sharp, and carefully used so as to avoid splitting the arms or 
 cutting too deeply into the old wood, good work may be done with them. 
 
 Disposal of Prunings. After the pruning is finished, the "brush" 
 or cuttings must be removed. This is much facilitated if the pruners 
 are careful in placing the wood they remove. The usual method is to 
 place the wood from two adjoining rows in the space between them, 
 either in a long line or in piles between four vines.
 
 52 
 
 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 These rows or piles can then be carried by hand or with a hay fork 
 and concentrated in large piles in the avenues or on the borders of the 
 vineyard, where they are burned as soon as sufficiently dry. The heat 
 from these fires is so great that it sometimes injures neighboring vines, 
 especially if the burning is deferred until the starting of the buds. 
 A better method is to use a brush burner. One form of brush burner 
 is shown in Fig. 21. This consists of an iron truck with a perforated 
 bottom. A fire is started in the truck, which is then drawn slowly 
 
 Fig. 21. Vineyard brush burner. 
 
 down a free row by a quiet horse trained to the work. Two men collect 
 the "brush" in the adjoining row r s and throw it into the moving truck, 
 where it burns without danger of injuring the vines, and at a lower 
 temperature than in the large piles. The ashes are distributed equally 
 over the vineyard. The method is difficult to adapt to trellised vine- 
 yards or to vines with fruit canes. 
 
 Gathering the brush with a hay rake is sometimes done, but is not 
 satisfactory and is apt to injure the vines unless the rows are far 
 apart. In some countries the vine prunings are used for fuel, for 
 manure, and even for cattle feed, after cutting and crushing. The 
 labor cost in California seems at present to prevent economical util- 
 ization in any of these ways.
 
 BULLETIN 241-246 V INE PRUNING IN CALIFORNIA 53 
 
 Principle of Economy. The skillful pruner directs as much as 
 possible of the energy and growth of the plant into the permanent 
 framework of the vine and into its fruit. The unskillful pruner allows 
 the vine to grow canes, arms, or branches where they are not wanted 
 and which must be cut off later. This is not only a complete loss to 
 the vine thus deprived of all the removed material which ought to 
 have gone into its permanent framework but the large wounds made 
 are a source of weakness and shorten the life of the vine. The skillful 
 pruner vitalizes the vigor of the vine by making it bear all the fruit 
 it is capable of bringing to perfection. He properly distributes the 
 fruit buds, leaving on each cane, arm, or vine just the number needed, 
 without running the risk, on the one hand, of weakening the vine with 
 an oversupply of poor fruit, or, on the other hand, of forcing it to 
 excessive vigor and sterility. 
 
 To avoid waste in the development of a young vine, the pruner 
 must have a clear idea of the form he wishes to give it. He must then, 
 by appropriate and timely removal of buds and shoots, force the growth 
 into those parts which are to form the permanent framework of his 
 ideal vine. No cane, arm, or division should be allowed to grow more 
 than one season which is not destined to be part of the final skeleton 
 of the mature plant. In this way the vine will not only attain the 
 desired form but will quickly reach bearing stature and be free from 
 the large wounds, which are one of the main causes of premature aging. 
 Part II of this bulletin will contain specific directions for applying 
 these principles to the principal vines and regions of California.
 
 PART II 
 
 THE PRACTICE OF PRUNING 
 
 Pruning Systems. The systems of pruning applied to the vine are 
 innumerable. These systems differ in the form given to the body of 
 the vine and in the management of the annual growth. Some of the 
 differences depend on variations in the nature of the vines, on the 
 cultural and growing conditions of the district, and on the objects of 
 the grower. Others are unessential and merely a matter of taste. The 
 best system is that which is most adapted to all the conditions of the 
 particular vineyard. Any system which does not take into account 
 the nature of the vine is defective. 
 
 Ideals of Pruning. Before commencing work the pruner should 
 form a mental picture of an ideal vine of the form desired. Vines are 
 subject to so many accidents of weather, cultivation, and disease that 
 even with the greatest care and skill it may be impossible to obtain a 
 single ideal vine in the vineyard. The ideal vine, however, must exist 
 in the pruner 's mind, or all his vines will be unnecessarily defective. 
 With this ideal constantly in mind, he is able to take such measures 
 as will, as much as possible, direct the energies of the vine in the right 
 direction and counteract all contrary influences, thus making each vine 
 approach as nearly as possible the perfect model. 
 
 This mental ideal is particularly necessary in the treatment of 
 young vines. Only when it is strongly impressed on the imagination 
 is it possible to use such means and measures as will most rapidly and 
 economically bring the vine to profitable maturity. 
 
 In the following account of the principal systems of pruning 
 adapted to Californian conditions a description is first given of an 
 ideal mature vine in full bearing. This is followed by a discussion 
 of methods of handling a young vine to make it approach as nearly 
 as possible this ideal, and finally by an account of the regular pruning 
 necessary to make the vine produce maximum crops to a respectable 
 old age. 
 
 Californian Systems. The systems of pruning in use in California 
 may be divided into two classes, according to the arrangement of the 
 arms on the trunk of the vine. In the common systems there is a 
 definite head to the trunk, from which all arms arise symmetrically at
 
 
 56 
 
 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION 
 
 nearly the same level. The vines of these systems may be called 
 "headed vines." In the other systems the trunk is elongated four 
 to eight feet and the arms are distributed regularly along the whole 
 or the greater portion of its length. The vines of these systems, owing 
 to the rope-like form of the trunks, are called ' ' cordons. ' ' 
 
 Wild vine from Caucasia (Vitis viniferti). 
 The source of our cultivated grapes. 
 
 The headed vines are divided according to the length of the vertical 
 trunk into high, 2-3 feet, medium, 1-1 1/2 f ee t, an d l w > 0-6 inches. 
 The cordons may be vertical or horizontal, according to the direction 
 of the trunk, which is from four to eight feet long. The horizontal 
 cordons may be single (unilateral} or composed of two branches ex- 
 tending in opposite directions (bilateral}. Double and even multiple 
 vertical cordons occur, but they have no advantages and are inad- 
 visable.
 
 BULLETIN 241-246 yiNE PRUNING IN CALIFORNIA 57 
 
 The arrangement of the arras of a headed vine may be symmetrical 
 in all directions at an angle of about 45 degrees. Such a vine is said 
 to be " vase-formed," though the hollow center which this term implies 
 is not essential. This is the form used in the great majority of our 
 vineyards whether of wine, raisin, or shipping grapes. It is suitable 
 for the "square" system of planting and cross-cultivation. Where 
 vines are planted in the avenue system, particularly when trellised, 
 and where cross-cultivation is impossible, the arms are given a "fan- 
 shaped" arrangement in a vertical plane. This arrangement is essen- 
 tial for the economical working of trellised vines. 
 
 On the vertical or upright cordon the arms are arranged at as 
 regular intervals as possible on all sides of the trunk from the top to 
 within twelve or fifteen inches of the bottom. On the horizontal cordon 
 the arms are arranged similarly, but as nearly as possible on the upper 
 side only of the trunk. 
 
 Each of these systems may again be divided into two sub-systems, 
 according to the management of the annual growth or canes. In one, 
 spurs of one, two, or three eyes are left for fruit production. This 
 system is called short or spur pruning. In the other, long canes are 
 left for fruit production (long or cane pruning}. In rare cases an 
 intermediate form is adopted in which long spurs or short canes of 
 five or six eyes are left. In cane pruning, each fruit cane is accom- 
 panied by one or two short renewal spurs. These must also accompany 
 half-long pruning. Systems of pruning, where only long canes are left 
 without renewal spurs, are not in use in California. In all systems 
 replacing spurs are left wherever and whenever needed. 
 
 Other modifications are introduced by the manner of disposal of 
 the fruit canes. These may be tied up vertically to a stake driven at 
 the foot of each vine, or bowed in a circle and tied to this same stake, 
 or they may be tied laterally to wires stretching along the rows in a 
 horizontal, ascending, or descending direction. 
 
 The different systems differ therefore in: (1) the shape, length, 
 and direction of the trunk; (2) the arrangement of the arms; (3) the 
 use of fruit spurs or fruit canes with renewal spurs; (4) the disposal 
 of the fruit canes. 
 
 The principal possibilities are shown in the following table : 
 
 A. HEAD PRUNING: VASE FORM 
 
 i TT ti * v f ^1 ( a ) ^" ru it spurs or 
 
 o r bj u>, 1(6) Half-long canes and renewal spurs or 
 
 3. Lo^Tunk 1 J < c > Fruit Ca " 6S and renewal
 
 58 
 
 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION 
 
 B. HEAD PRUNING: FAN SHAPED; TRELLISED 
 
 1. High trunk: Fruit canes and renewal spurs; canes descending. 
 
 2. Medium trunk: Fruit canes and renewal spurs; canes horizontal or ascending. 
 
 C. CORDON PRUNING 
 
 1. Vertical: Spur; half-long; cane. 
 
 2. Horizontal-unilateral: Spur; half -long; cane. 
 
 3. Horizontal -bilateral: Spur; half -long; cane. 
 
 All possible combinations indicated by this table represent twenty- 
 four variations. Some of these combinations, however, are not used 
 and some are rare. The common ones are shown in Figs. 22, 23, 24, 25, 
 and 26. 
 
 ABC 
 
 Fig. 22. Forms of head pruning: A, spur pruning with high trunk; B, spur 
 pruning with medium trunk; C, half -long with medium trunk. 
 
 Fig. 22 B represents a headed, vase-formed vine, with a medium trunk and 
 short fruit spurs. This is the common system used in all parts of California, 
 and is suited for all small growing vines which bear on the lower buds, for most 
 wine grapes and for Muscats. The unit of pruning in this case is a fruit spur 
 of 1, 2, or 3 internodes, according to the vigor of the variety and of the indi- 
 vidual cane. 
 
 Fig. 22 A differs from 22 B only in the higher trunk and longer arms. It is 
 commonly used for Tokay and other large growing varieties, especially when 
 growing in rich soil and when planted far apart. 
 
 Fig. 22 C has the same form of body as A and B, except that the arms are 
 somewhat less numerous. The unit of pruning is a short fruit cane of four to 
 five internodes, accompanied by a renewal spur of one internode. It is suited 
 for vigorous table grapes, which do not bear well on short spurs, being used 
 especially for the Cornichon and Malaga in rich soil. This is a difficult system 
 to keep in good shape owing to the tendency for all the vigor to go to the 
 growth on the ends of the fruit canes. It is difficult to obtain vigorous canes on 
 the renewal spurs. Occasional short pruning is usually necessary to keep the 
 vines in proper shape.
 
 BULLETIN 241-246 
 
 VINE PRUNING IN CALIFORNIA 
 
 59 
 
 Fig. 23 A is similar to 22 C in form, but the number of arms is still further 
 reduced to 2, 3, or at most 4. The unit of pruning is a fruit cane of 2^ to 3% 
 feet with its renewal spur. Owing to the length of the fruit canes, they require 
 support and are tied to a high stake. 
 
 A B 
 
 Tig. 23. Forms of head pruning: A, vertical fruit canes and renewal spurs; 
 B, bowed fruit canes and renewal spurs. 
 
 This method is used in a large number of vineyards with Sultanina, 
 Sultana, and certain wine grapes, especially Semillon and Cabernet. 
 It is not to be recommended, as it has several serious defects. 
 
 The difficulty of obtaining new wood from the renewal spurs is even 
 greater than in the system shown in Fig. 22 C. The length and vertical 
 position of the fruit canes cause the main growth and vigor of the vine 
 to be expended on the highest shoots. (See Physiological Principles 
 5 and 6, p. 26, Pt. I) The renewal spurs are thus so shaded that, even 
 though their buds start, the shoots make but a weak growth. The
 
 60 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION 
 
 result is that at the following pruning all the good new wood is at the 
 top of the fruit canes of the previous year, where it cannot be utilized. 
 The pruner then has to choose between reverting to spur pruning and 
 getting no crop, or using the weak growth from the renewal spurs for 
 fruit canes, in which case he may get blossoms but little or no fruit 
 of any value. 
 
 Other defects of this method are that the fruiting shoots are ex- 
 cessively vigorous and therefore often tend to drop their blossoms with- 
 out setting, and the fruit when produced is massed together so that 
 it ripens unevenly and is difficult to gather. It also requires a tall 
 and expensive stake. 
 
 Fig. 23 B represents an improvement on the last system. It differs 
 only in the method of treating the fruit canes. These are bent over in 
 the form of a circle and tied by their middle part to a stake which may 
 be smaller and lower than that needed for the vertical canes. 
 
 This bowing of the canes has several useful effects. The change 
 of direction moderates the tendency of the vigor of the vine to expend 
 itself only on the terminal shoots. More shoots are therefore formed 
 on the fruit canes and as their vigor is somewhat decreased they tend 
 to be more fruitful. The slight mechanical injury caused by the bend- 
 ing operates in the same direction. (See Physiological Principle 4, 
 p. 25, Pt. I.) 
 
 The excess of vigor being thus diverted from the fruit canes causes 
 the renewal spurs to form vigorous shoots, which soon grow above the 
 fruit shoots and obtain the light and air they need for their proper 
 development. This method is used successfully for certain wine grapes 
 such as Riesling, Cabernet, and Semillon. It is unsuited to large 
 vigorous varieties or for vines on rich soil planted wide apart. In 
 these cases two fruit canes are usually insufficient, and, if more are 
 used, the grapes and leaves are so massed together that they are subject 
 to mildew and do not ripen evenly. The bowing and tying of the 
 qanes requires considerable skill and care on the part of the workmen. 
 
 The body, arms, and annual pruning of the system shown in Fig. 24 
 are similar to those of Fig. 23, with the exception that the arms are 
 given a fan-shaped arrangement in one plane. It differs in the dis- 
 posal of the fruit canes, which are supported by a trellis stretching 
 along the row from vine to vine. 
 
 This method is largely used for the Sultanina (Thompson's Seed- 
 less), and is the best system for vigorous vines which require long 
 pruning, wherever it is possible to dispense with cross-cultivation. It 
 is also suitable for any long-pruned varieties when growing in fertile 
 soil.
 
 BULLETIN 241-246 
 
 VINE PRUNING IN CALIFORNIA 
 
 61 

 
 62 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 Fig. 25 is a photograph of a four-year-old Emperor vine, illus- 
 trating the vertical cordon system. It consists of an upright trunk 
 1/2 feet high with short arms and fruit spurs scattered evenly and 
 symmetrically from the top to within fifteen inches of the bottom. 
 This system is used in many Emperor vineyards in the San Joaquin 
 
 Fig. 25. Single vertical cordon with fruit spurs. 
 
 Valley. Its advantages are that it allows the large development of 
 the vine and the large number of spurs which the vigor of the Emperor 
 demands without, on the one hand, crowding the fruit by the prox- 
 imity of the spurs or, on the other, spreading the vine so much that 
 cultivation is interfered with. It also permits cross-cultivation. 
 
 One of its defects is that the fruit is subjected to various degrees 
 of temperature and shading in different parts of the vine and the 
 ripening and coloring are often uneven. A more vital defect is that
 
 BULLETIN 241-246 VINE PRUNING IN CALIFORNIA 63 
 
 it cannot be maintained permanently. The arms and spurs at the top 
 of the trunk tend to absorb the energies of the vine and the lower arms 
 and spurs become weaker each year until finally no growth at all is 
 obtained below. After several years most of the vines therefore lose 
 their character of cordons and become simply headed vines with ab- 
 normally long trunks. (See Figs. 64, 65.) 
 
 The cordon can be reestablished in this case by allowing a vigorous 
 sucker to develop one year from which to form a new trunk the next. 
 The following year the old trunk is removed entirely. An objection 
 to this method is that it makes very large wounds in the most vital 
 part of the vine the base of the trunk. 
 
 Fig. 26. Unilateral horizontal cordon with fruit spurs. 
 
 Fig. 26 is a photograph of a four-year-old Colombar vine, illus- 
 trating the unilateral, horizontal cordon system. It consists of a trunk 
 about seven feet long, supported horizontally by a wire two feet from 
 the ground. Arms and spurs are arranged along the whole horizontal 
 part of the trunk. 
 
 This system accomplishes the same purposes as the vertical cordon. 
 It allows a large development of the vine and of numerous fruit spurs 
 without crowding. It is superior to the vertical cordon in the distri- 
 bution of the fruit, which is all exposed to approximately the same 
 conditions owing to the uniform distance of the fruit spurs from the 
 ground. All parts of the trunk producing an annual growth of wood 
 and fruit are equally exposed to light and the tendency of the growth 
 to occur principally at the part of the trunk farthest removed from 
 the root is counteracted by the horizonal position. There is not the 
 same difficulty therefore in maintaining this form of vine permanently 
 that there is with the vertical cordon.
 
 64 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 This system should not be used for small weak vines, whether the 
 weakness is a characteristic of the variety or due to the nature of the 
 soil. It is suited only to very vigorous varieties, such as Emperor, 
 Almeria, and the Persian grapes, when these are growing far apart 
 in rich, moist soil. 
 
 Periods of Development. The first year in the life of the vine is 
 devoted to developing a vigorous root system ; the next two or three 
 years to building up a shapely trunk and head, and a like period to 
 forming the full complement of arms. At the end of from five to nine 
 years the framework of the vine is complete and should undergo no 
 particular change of shape except a gradual thickening of trunk and 
 arms. 
 
 There are, therefore, several periods in the life of the vine, with 
 varying objects, and the methods of pruning must vary accordingly. 
 These periods do not correspond exactly to periods of time, so that it 
 may be misleading to speak of pruning a two-year-old 1 or a three- 
 year-old vine. One vine under certain conditions will reach the same 
 stage of development in two years that another will reach only in three 
 or four years under other conditions. The range of time of these 
 periods is about as follows : 
 
 First period Formation of a strong root system 1 to 2 years 
 
 Second period Formation of stem or trunk 1 year 
 
 Third period Formation of head 2 to 3 years 
 
 Fourth period Complete development of the arms 2 to 3 years 
 
 Total time of formation of framework 6 to 9 years 
 
 Jnder exceptionally favorable conditions the first and second 
 periods may be included in the first year and a completely formed 
 vine may be obtained in five years. 
 
 Before Planting. Cuttings, one-year-old rooted vines, or bench 
 grafts are used for planting. In all cases they need some attention 
 from the pruner. In Fig. 27 are shown the three forms of cuttings 
 used in California. They differ only in length. The shortest eight 
 to ten inches, are best suited for planting in the nursery; those of 
 twelve to fourteen inches for planting in the field. The longest cut- 
 tings, sixteen to eighteen inches, are to be recommended only for the 
 driest soils. In all cases they are cut at the bottom just below a bud. 
 This facilitates the healing over of the base, as roots and healing 
 tissue form most abundantly near a node. The top may be cut just 
 
 1 Age of Vines. There is a diversity of usage in denoting the age of a vine. 
 In some localities a one-year-old vine means a vine that is in its first year; in 
 others it means a vine that has completed its first year and is in its second. The 
 former method is adopted here as the most convenient.
 
 BULLETIN 241-246 
 
 VINE PRUNING IN CALIFORNIA 
 
 65 
 
 above a bud, so as to leave the protecting diaphragm or about one inch 
 of internode, as in the figure. 
 
 Fig. 28 shows a bundle of good one-year-old rooted vines as they 
 are usually prepared at the nursery. Before planting they must be 
 pruned. The method of pruning depends on the size and shape of the 
 vine and on the method of planting adopted. 
 
 Fig. 27. Forms of cuttings. 
 
 Fig. 28. One-year-old rooted vines. 
 
 Fig. 29 shows a good rooted vine of average size having a single 
 cane at the top and several good roots at the bottom. The usual way 
 to prune this is to shorten the cane to one or two buds and the roots 
 to two or four inches, according to their size. Shortening the cane 
 makes the vine less liable to dry out before rooting and forces the 
 growth from the lower buds which produce more vigorous shoots. The 
 roots are shortened so that there will be no danger of the ends being 
 turned upwards when planted. If they are to be planted in a large 
 hole, they may be left as long as five or six inches ; if to be planted with 
 a crowbar or dibble, they must be cut back to half an inch. 
 
 There is little if any advantage in leaving long pieces of roots. 
 They are not feeding roots and are of no use to the vine until they
 
 UNIVERSITY Of CALIFORNIA EXPERIMENT STATION 
 
 develop feeding rootlets. This they will do as well or better if short- 
 ened instead of being left full length. The main advantage of a rooted 
 vine over a cutting is that it forms rootlets more easily and rapidly. 
 There may be a slight advantage in leaving three or four inches of the 
 sound well grown roots, as the reserve matters they contain probably 
 promote a better growth of rootlets, but little or no difference has been 
 noted between the growth of vines of which the roots have been short- 
 
 Fig. 29. Booted vine with 
 single cane. 
 
 Fig. 30. Booted vine with 
 two canes. 
 
 ened to one-half inch and those which have been left longer. "Where 
 the roots are left long, moreover, more care and time are needed in 
 planting. 
 
 If the rooted vine has several canes, all but one should be removed 
 entirely, and this one shortened to one or two eyes. The one left should 
 be that which is strongest, has the best buds, and is the best placed. 
 Fig. 30 shows the removal of a cane growing horizontally and two 
 buds left on a vertical cane. Where a horizontal cane is left it should 
 be cut back to the base bud. Otherwise the main growth may occur at 
 a higher bud and the vine will have a crook which will result in a badly 
 formed trunk.
 
 BULLETIN 241-246 
 
 VINE PRUNING IN CALIFORNIA 
 
 67 
 
 If canes are growing from different joints, as in Fig. 31, it is usually 
 best to leave the lowest cane if they are equally vigorous. This brings 
 the buds from which growth will come nearer to the roots and leaves 
 less of the original cutting, which are advantages. The upper joint 
 between the canes is, moreover, often more or less decayed or imperfect. 
 
 Fig. 32 shows a vine pruned and ready for planting. Bench 
 grafted vines are pruned in exactly the same way, but in this case it 
 is necessary to take great care that all roots from near or above the 
 union and all canes from near or below the union are removed. 
 
 Fig. 31. Booted vine with 
 canes at two levels. 
 
 Fig. 32 Hooted vine pruned 
 ready for planting. 
 
 Fig. 33 shows a vine grown in the nursery from an unnecessarily 
 long cutting. It was grown in warm, well drained soil, so that roots 
 have formed at three levels from different nodes. Even in this soil, 
 however, the conditions were not favorable for root growth at the 
 bottom, so the last two nodes have formed no roots. If the cutting 
 had been of five nodes instead of eight, it would have made* a much 
 better vine. The roots would have been less numerous but more vigor- 
 ous. Such a vine can be pruned in one of three ways, according to the
 
 68 
 
 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 character of the ground in which it is to be planted. In any case, the 
 bottom two joints, without good roots, are cut off. If the soil where 
 the vine is to be planted is deep and dry, the roots at the next three 
 joints may be left and shortened to about one inch, as indicated in the 
 figure. The roots are so numerous that none of them have grown large 
 (see Physiological Principles, p. 25, Pt. I), and nothing would be 
 gained by leaving them longer. For ordinary soils it would be better 
 to remove the lower three joints and for wet soils the lower five. 
 
 
 
 Fig. 33. Nursery vine with 
 roots at different levels. 
 
 Fig. 34. Eesult of planting too 
 deep. 
 
 Fig. 34 shows the result of planting an unnecessarily long cutting 
 or rooted vine. It represents the lower part of the underground por- 
 tion of a vine two or three years old. The cutting or rooted vine was 
 at least three joints too long, and the lowest part not only furnishes 
 no roots of any value but is liable to decay, which may spread into the 
 rest of the vine. 
 
 Fig. 35 shows the root growth during the first year in the field of 
 a rooted vine of which the roots had been properly pruned and planted 
 at the right depth. 
 
 Planting. Cuttings made as directed are planted with the second 
 bud at the level of the ground, leaving only one bud above. Rooted 
 vines -are planted with the two buds just above the surface. Bench
 
 BULLETIN 241-246 
 
 VINE PRUNING IN CALIFORNIA 
 
 69 
 
 In 
 
 grafts are planted with the union just one inch above the surface, 
 the last case the soil must be hilled up so as to cover the union. 
 
 First Growing Season. The treatment during the first spring and 
 summer will depend on what growth the vines are expected to make 
 and on whether the vines are staked the first year. 
 
 With cuttings and with both rooted vines and grafts where the 
 growth will be moderate staking the first year is unnecessary, though 
 it has some slight advantages. In these cases no pruning of any kind 
 is necessary until the winter following the planting, except in the case 
 
 Fig. 35. Eoots of a young vine that had been properly pruned before 
 planting. 
 
 of bench grafts. The pruning in the last case is confined to the re- 
 moval of the suckers from the stock and roots from the scion. If the 
 stocks have been well disbudded by the nurseryman, few suckers will 
 develop. In moist soil the scion roots may develop vigorously, and 
 must be removed before they grow too large or they may prevent the 
 proper development of the resistant roots. 
 
 The removal of roots should usually be done some time in July. 
 For this purpose the hill of soil is scraped away from the union and 
 after the scion roots and suckers are removed it is replaced. In this 
 second hilling up the union should be just barely covered so that the
 
 70 
 
 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION 
 
 soil around the union will be dry and unfavorable to a second growth 
 of roots. Later in the season, about September, the soil should be 
 removed entirely from around the union and any new roots that may 
 have formed removed. The union is then left exposed to harden and 
 mature, so that it will pass the winter without injury. 
 
 "is 
 
 Fig. 36. Growth of vine during the first summer. 
 
 Fig. 36 shows a grafted vine in July after the union has been un- 
 covered for root cutting. It represents a good average vine at this 
 period. Such a vine will usually support itself without a stake but 
 if a stake is used it should be tied to it loosely. If the main shoot is 
 kept upright, it will be easier to produce a well formed vine. 
 
 No disbudding, thinning of shoots, or topping need be done in this 
 case. The object is to have as abundant a growth of foliage as possible
 
 BULLETIN 241-246 
 
 VINE PRUNING IN CALIFORNIA 
 
 71 
 
 in order to stimulate a vigorous and abundant root development. (See 
 Physiological Principle No. 1, p. 25, Pt. I.) 
 
 In some cases, where very good rooted vines of vigorous varieties 
 are planted in rich soil abundantly supplied with water, it is desirable 
 to disbud the vine early in order to throw all its energies into the single 
 main cane. In such cases staking before or just after planting are 
 necessary, and methods similar to those described for the second season 
 are used. 
 
 First Winter Pruning. At the end of the first growing season an 
 average good vine will have produced from three to five canes, the 
 longest of which will be from two to three feet long. (See Fig. 37 A.) 
 
 Fig. 37. Vine at end of first growing season. First winter pruning; A, 
 before pruning; c, c, places for making cuts; B, after pruning and staking. 
 
 Soon after the leaves have fallen in December or early in January, 
 the vines should be pruned. The method is precisely similar to that 
 used for rooted vines before planting except that the main roots are 
 not touched. All the canes are removed entirely except one. This one 
 should be well matured, at least at the base, and should have well 
 formed eyes. It is shortened to two eyes. (See Fig. 37 B.) It is well 
 also to cut off all shallow roots within three or four inches of the sur- 
 face. This is necessary in the case of grafted vines if any have escaped 
 the summer root cutting. 
 
 Some of the vines may have made an exceptionally large growth. 
 Such vines may sometimes possess a cane large enough from which 
 to start the trunk in the way described later for the second winter 
 pruning. 
 
 Staking. If the vines have not been staked before, the stakes 
 should be driven soon after pruning and before the starting of the 
 buds. 
 
 In order to preserve the alignment of the vineyard the stakes should 
 be driven on the same side of every vine at a uniform distance. The
 
 72 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION 
 
 best distance is about two inches. If driven closer they may injure 
 large roots, or even the main underground stem if the vines have not 
 been carefully planted vertically or slanting toward the side on which 
 the stake is to be placed. 
 
 The side on which the stake should be placed depends on the 
 direction of the prevailing winds during the growing season. This 
 side is the leeward. That is, the stake should be so placed that the 
 wind will press the vine toward the stake instead of away from it. This 
 will much facilitate the work of keeping the vine upright and attached 
 to the stake. If the vine is on the other side the pressure of the wind 
 will stretch the string tight and the swaying of the vine will gradually 
 wear the string until it breaks, necessitating retying. By carefully 
 observing this rule very few vines will require retying even if weak 
 material like binding twine is used. 
 
 Second Summer Pruning. Before the starting of the buds, in the 
 spring following the planting, most of the vines appear about the same 
 as when they were planted. ( See Fig. 38. ) There is, however, a very 
 notable difference in that they have well developed root systems in the 
 soil where they were formed. The result is that they make a much 
 more prompt and early start and will produce a much larger growth 
 than they did the first season. For this reason they require very care- 
 ful attention from the pruner during the spring and summer of the 
 second season. Vines neglected at this time, in this respect, may make 
 as large a growth, but a large part of it will be wasted, the vines will 
 be misformed, and it will require from one to two years longer to de- 
 velop a suitable framework and to bring them into bearing, even though 
 they are properly handled during subsequent years. The more vigor- 
 ous the vines the more necessary it is to handle them properly during 
 this period. 
 
 The main object during this second growing season is to develop a 
 single, strong, vigorous and well ripened cane from which to form the 
 permanent trunk of the vine. 
 
 This is done by concentrating all the energies of the vine into the 
 growth of a single shoot. As soon as the buds start or when the most 
 precocious has developed a shoot of a few inches in length, the vines 
 should be disbudded (Fig. 38 A). This consists in rubbing off with 
 the hand all buds and shoots except the largest and best placed. The 
 lowest, upright shoot is usually the best. Leave only those which will 
 make a straight vine. It is better to leave a less developed bud than 
 a shoot which, when it grows, will make an awkward crook with the 
 underground stem.
 
 BULLETIN 241-246 
 
 VINE PRUNING IN CALIFORNIA 
 
 73 
 
 After this disbudding, the shoot left will grow rapidly, as it re- 
 ceives all the energies of the root system. When it has grown from 
 ten to fifteen inches it should be tied to the stake (Fig. 38 B). Unless 
 this is done it is liable to be broken off by a heavy wind, owing to its 
 soft, succulent texture. 
 
 At the tying up of the reserved shoots all new shoots which have 
 developed since the first disbudding should be removed. The shoots 
 should be tied up loosely, as they are soft and easily injured, and they 
 should be brought around carefully to the windward side of the stake. 
 
 Fig. 38. Growth and treatment of the vine during the second season, c, c, 
 place where shoots are removed. 
 
 The shoots will require tying once more when they have grown 
 another foot or eighteen inches. There will then be two ties, one at 
 two or three inches from the top of the stake and the other at about 
 the middle. If the vines have a tall stake and are to be headed very 
 high, another tying higher up may be needed later (Fig. 38 C). 
 
 "With vines making only a moderate growth, no other pruning will 
 be needed until the winter. Exceptionally vigorous vines, however, 
 may make a cane eight, ten or more feet long. Such a cane is heavy 
 and is very likely to break the ropes by which it is attached to the 
 stake. In this case it may break off at the bottom, or at least will form 
 an awkward crook near the ground when it matures. In either case 
 it is difficult to form a good trunk the following year. Even when the 
 ties do not break, the cane will not be well suited for the commencement
 
 74 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 ft 
 
 of a trunk, as the joints will be so long that it will be impossible to 
 leave enough well placed buds at the winter pruning. 
 
 Both these difficulties are avoided. by timely topping. When such 
 vigorously growing canes have grown twelve or eighteen inches above 
 the top of the stake they are cut back about level with the stake ( Fig. 
 38 D). This is most conveniently done with a long-bladed knife or 
 piece of split bamboo. After topping, the cane ceases to grow in length 
 and laterals start at most of the joints. It is less exposed to the action 
 of the wind and the laterals supply the buds needed for forming the 
 vine at the winter pruning. 
 
 The result of the second season's growth, then, has been to produce 
 a single vigorous cane with or without laterals. This is the cane which 
 is to develop into the final and permanent trunk of the vine. It must 
 not only be large and vigorous but must be properly matured. If the 
 vine is allowed to grow too late in the season, an early frost may de- 
 stroy the unmatured cane and much of the results of the year 's growth 
 will be wasted. Such a frost may indeed kill the entire vine. Grafted 
 vines are particularly liable to injury from this cause, as, if they are 
 killed down to the union, they are completely ruined. Ungrafted vines 
 when killed to the ground may be renewed from a sucker the following 
 year. This sucker, however, is likely to grow with such vigor that it is 
 even more liable to injury from an autumn frost than the original 
 shoot. 
 
 This late growth is much more likely to occur with young vines than 
 with old. The old vines stop growing earlier because their energies 
 are directed into the crop and as they produce a larger amount of 
 foliage they draw more upon the moisture of the soil, which therefore 
 dries out earlier. 
 
 Late growth of the young vines must be prevented and the wood 
 matured before frost if .possible. This is accomplished by means which 
 promote the drying of the soil in autumn. Late irrigations should be 
 avoided. Cultivation should usually stop by midsummer. In very 
 moist, rich soils it is often an advantage to grow corn, sunflowers, or 
 similar crops between the rows of vines to take off the surplus moisture. 
 In some cases it is good practice to let the summer weeds grow for the 
 same purpose. 
 
 Second Winter Pruning. With vines which have been treated as 
 described, and to which no accident has happened, the second winter 
 pruning is very simple. It consists only in cutting back the single 
 cane which has been allowed to grow to the height at which it is desired 
 to head the vine.
 
 BULLETIN 241-246 
 
 VINE PRUNING IN CALIFORNIA 
 
 75 
 
 Fig. 39 represents a vine which has been cut back to form a low 
 medium head. It consists of a single cane which with the older wood 
 at the base reaches nearly to the top of the stake, or fifteen inches. If 
 properly treated this will develop into -a vine with a trunk of about 
 twelve inches, though this length can be modified slightly, as will be 
 explained later. 
 
 This cane consists of about seven or eight joints or internodes, with 
 an equal number of well formed eyes and an indefinite number of 
 
 Fig. 39. Second winter pruning for head of medium height. 
 
 dormant buds, principally near the base of the cane or junction of the 
 one and two-year-old wood. Only the buds on the upper half of this 
 cane should be allowed to grow. These buds about four should give 
 six to-eight bunches of grapes and four, six, or eight shoots from which 
 to form the spurs at the following winter pruning. 
 
 Fig. 40 represents a vine which has been cut back to form a high 
 head. The cane is about twenty-four inches long and may be used to 
 form a trunk eighteen inches high, though this height can be modified 
 as in the last case. As with the shorter cane, only the buds on the 
 upper half will be allowed to produce shoots. These about six 
 should give ten to twelve bunches and the shoots necessary for the 
 formation' of spurs.
 
 76 
 
 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION 
 
 Fig. 41 represents a vigorous vine which had been topped during 
 the summer, and consequently had formed well developed laterals. 
 This vine has been cut back to the same length as that shown in Fig. 40. 
 One bud has been left of each* lateral giving thus three more buds to 
 produce grapes and shoots. 
 
 Fig. 40. Second winter pruning 
 for high head. 
 
 Fig. 41. Second winter pruning 
 of very vigorous vine. 
 
 In all cases a full internode has been left above the top bud. This 
 is done by cutting through the first bud above the highest which it is 
 desired to have grow. This cut is made in such a way as to destroy 
 the bud but to leave the diaphragm intact and part of the swelling of 
 the node. This upper iuternode is left partly to protect the upper
 
 BULLETIN 241-246 yiNE PRUNING IN CALIFORNIA 77 
 
 bud, but principally to facilitate tying. By making a half hitch around 
 this internode the vine is held very firmly. If the swelling at the node 
 of the destroyed bud is not left, many vines will be pulled out of the 
 hitch when they become heavy with leaves and supple with the flow of 
 sap in the spring. 
 
 In tying the vines, no turns or hitches must be made around any 
 part except this upper internode. A hitch below the top bud will 
 result in a crook-necked vine as the top will bend over in the summer 
 under the weight of the foliage. A hitch lower down is even more 
 harmful, as it will girdle and strangle the vine. 
 
 A second tie about half way from the upper internode to the ground 
 is always necessary to straighten the cane. Even if the cane is straight 
 when pruned, a second tie is needed to keep it from curving under the 
 pressure of leaves and wind in the spring. For high-headed vines three 
 ties are usually necessary placed, as shown in Figs. 40 and 41. 
 
 For the top tie, wire is particularly suitable. It holds better than 
 twine and does not wear. Even though it is not removed, it does no 
 harm, as the part around which it is wound does not grow. The lower 
 ties should be of softer material, as wire has a tendency to cut into the 
 wood. They should be placed so that the cane is able to expand as it 
 grows. With thin and especially with round stakes this means that 
 the tie must be loose. "With large, square stakes there is usually suffi- 
 cient room for expansion, even when the twine is tied tight. 
 
 However careful the pruner, many of the vines cannot be pruned 
 quite so simply as those described. These methods therefore must 
 often be modified, keeping these vines in mind as ideals which the 
 imperfect vines are made to approach as nearly as may be. 
 
 Some of the vines may not make a sufficient growth of cane to be 
 tied up in the way indicated. Such vines should be pruned back again 
 to two buds as at the previous winter pruning, and special care taken 
 during the following summer to develop a good cane. Vines in which 
 the development of the tying-up cane is thus delayed a year will usually 
 make a very vigorous growth the following summer and must be 
 topped. The result at the following winter pruning will be a vigorous 
 cane with laterals, which should be pruned like the vine in Fig. 41. 
 All vines which have not made a growth of well developed, mature 
 cane of the length desired should be cut back to two buds. This length 
 will usually be at least twice that of the desired height of trunk because 
 the upper part of the cane is usually badly matured and with imperfect 
 buds. It is bad practice to cut canes to intermediate lengths, as this 
 results usually in crooked trunks and inevitably to variations in the 
 height of the heads of different vines.
 
 78 
 
 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION 
 
 If the suckering, disbudding, and thinning of shoots have been 
 neglected, there will be more than one cane on the vine. In this case 
 all but the strongest and best placed must be removed and this treated 
 like the single cane in Figs. 39 and 40. Unfortunately the strongest is 
 
 Fig. 42. Third spring, ready for 
 disbudding. 
 
 Fig. 43. Third spring, cane too 
 short. 
 
 often not the best placed. In fact, if tying up during the summer has 
 been neglected it is often the worst placed. The more vigorous the 
 vine the more likely is the position of the canes to be defective. This 
 is especially true of grafts on old vines, which should be treated like 
 exceptionally vigorous vines during the second growing season. In 
 these cases of neglected vines the best canes are often lying flat on the
 
 BULLETIN 241-246 VINE PRUNING IN CALIFORNIA 79 
 
 ground. It will require all the ingenuity and skill of the pruner to 
 get them into a more or less erect position, and at the best they will 
 result in crooked, misshapen vines. 
 
 By removing the soil from around the base of the vine the cane can 
 often be raised more easily and the bend will then be at least partially 
 in the underground stem, where it is less harmful. In the worst cases 
 it may be impossible to raise a cane. It is then necessary to cut all 
 the canes back to the old wood and to develop a new cane the next year. 
 
 Even if the main cane has been tied up, the removal of the other 
 canes, if they are numerous and large, makes many serious wounds at 
 the collar of the vine, which, in some cases, weaken the vine con- 
 siderably. 
 
 Third Summer Pruning. During the third season average vines, 
 such as those represented in Figs. 39 and 40, will produce their first 
 considerable crop and develop the canes from which will be formed 
 the first arms. 
 
 Fig. 42 represents such a vine soon after the starting of the buds 
 in spring. One vigorous shoot about three inches long has grown from 
 the old wood and five fruit buds have started above on the cane. All 
 the buds and shoots below the middle of the cane should be removed. 
 
 This will leave the four or five fruit buds and will give the vine 
 the opportunity to produce eight or ten bunches of grapes. These 
 buds will produce also at least four or five shoots. If the vine is very 
 vigorous and the season favorable, they may produce eight, ten or 
 more. 
 
 This figure will serve to illustrate how the height of the head can 
 be modified later. When the five shoots grow the height of the head 
 will be determined at the next winter pruning by which two of the 
 corresponding canes are left as spurs. If the highest two canes are 
 cut back to spurs and all others removed, the vine will be headed as 
 high as possible, as these two spurs form the two first arms which de- 
 termine the length of the trunk. If the lowest two canes are chosen 
 and all of the vine above them removed, the trunk will be made as low 
 as possible. Intermediate heights can be obtained by using some other 
 two adjacent canes and removing the rest. It is often advisable to 
 leave some extra spurs lower than it is desired to head the vine and to 
 remove these lower spurs the following winter after they have borne 
 a crop. For example, the three or four upper canes might be left, if 
 the vine is vigorous enough, and the lowest one or two of these removed 
 at the next pruning. This, however, is not often necessary with prop- 
 erly handled vines and is objectionable because it makes large wounds 
 in the trunk.
 
 80 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 Fig. 43 shows a vine of which the cane is too short. This was due 
 to the accidental breaking off of the upper part of the cane. In this 
 case it is best to remove all the buds and shoots but the uppermost two. 
 Otherwise the vine may head out too low. Such a vine will usually 
 make several shoots from each of the buds left, and while it will pro- 
 duce few grapes the current year, it will be in proper shape to produce 
 a good crop the following year. 
 
 During this spring it will be necessary to sucker and remove low 
 shoots at least once more. This can be done when the vines are hoed. 
 
 Tig. 44. Vineyard during the third summer. 
 
 If the vines grow vigorously, the shoots should be pinched when they 
 are eighteen to twenty-four inches long to protect them from the wind. 
 
 Fig. 44 shows a well grown vineyard towards the end of the third 
 summer. The vines shown produced at the rate of five tons per acre, 
 which may be considered about two-thirds of a full crop for full bearing 
 vines of the variety, under the soil and climatic conditions of the vine- 
 yard. The crop of one of these vines left on the vine until after the 
 fall of the leaves is shown in Fig. 45. 
 
 Third Winter Pruning. At the end of the third season's growth 
 the vine should have a straight, well developed trunk with a number 
 of vigorous canes near the top from which to form the arms. 
 
 Fig. 46 represents a well grown vine at this period. No shoots 
 have been allowed to grow on the lower part of the trunk and the five
 
 BULLETIN 241-246 yiNE PRUNING IN CALIFORNIA 
 
 81 
 
 1 
 
 
 
 Fig. 45. Crop at end of third season. 
 
 Fig. 46. Three-year-old vine ready for pruning.
 
 82 
 
 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION 
 
 buds allowed to grow above have produced nine vigorous canes. The 
 pruner should leave enough spurs to supply all the fruit buds that 
 the vine can utilize. The number, size, and thickness of the canes 
 show that the vine is very vigorous and can support a large crop. It 
 will depend somewhat on the variety how many buds should be left. 
 For a variety whose bunches average one pound, and which produces 
 two bunches to the shoot, twelve fruit buds should give about twenty- 
 four pounds or about seven tons per acre, if the vines are planted 12 
 by 6 feet, as these were. The number of spurs will depend on their 
 
 Fig. 47. Vine of Fig. 46 after pruning for vase-formed head. 
 
 length. Six spurs of two buds each will give the required number, but 
 as some of these canes are exceptionally vigorous they should be left a 
 little longer, in which case a smaller number of spurs will suffice. 
 
 When the number and length of the spurs is decided on, the canes 
 should be chosen which will leave these spurs in the most suitable 
 position for forming arms. This position will depend on whether we 
 want a vase-form or fan-shaped vine. In the first case, we choose those 
 which will distribute the spurs most evenly and symmetrically on all 
 sides, avoiding any which cross or point downwards. 
 
 In the second case, we choose only those canes which run in the 
 direction of the trellis, avoiding canes which stick out between the rows. 
 Downward pointing canes may be used in this case.
 
 BULLETIN 241-246 v! NE PRUNING IN CALIFORNIA 83 
 
 Fig. 47 shows the vine after pruning for a vase-formed head. The 
 primer has used two of the strongest canes to form two three-bud spurs 
 and three of medium vigor to form three two-bud spurs. The head 
 is of good shape, though some of the spurs are a little too low. One, 
 two, or three of these may be removed at the following winter pruning 
 and the permanent arms and head of the vine formed from canes 
 
 A B 
 
 Fig. 48. Three-year-old vines: A, pruned for a vase-formed, and B, for a 
 fan-shaped head. 
 
 which develop on the two highest spurs. If the vine were too high, 
 the head could be developed the next year from the three lowest spurs 
 and the upper part removed. 
 
 Fig. 48 shows vines of the same age of practically perfect shape. 
 Less spurs have been left because the vines were less vigorous. It is 
 easier to properly shape vines which make only a moderate growth 
 during the first three seasons. On the other hand, very vigorous vines
 
 84 
 
 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 can finally be brought into practically perfect shape and the somewhat 
 larger and more numerous wounds necessary are more easily healed 
 by a vigorous vine. 
 
 Fig. 49. Four-year-old vine pruned for vase-formed head. 
 
 Pruning After the Third Winter. For the pruner who under- 
 stands the pruning of young vines and has brought them to approxi- 
 mately the form represented in Figs. 47 and 48 the subsequent winter 
 pruning is very simple. It involves, however, one new idea the dis- 
 tinction between fruit and sterile wood.
 
 BULLETIN 241-246 
 
 VINE PRUNING IN CALIFORNIA 
 
 85 
 
 Up to the third winter pruning this distinction is not necessary; 
 first, because practically all the wood is fruit wood, and second, be- 
 cause the necessity of forming the vine controls the choice of wood. 
 From this time on, however, this distinction must be carefully made. 
 At each winter pruning a number of spurs of fruit wood must be left 
 to produce the crop to be expected from the size and vigor of the vine. 
 Besides these fruit spurs, it may be necessary to leave spurs of sterile 
 
 Fig. 50. Four-year-old vine pruned for high vase-formed head. 
 
 wood to permit of increasing the number of fruit spurs the following 
 year. 
 
 This will be made clear by comparing Figs. 48 A and 49. Fig. 
 48 A shows a vine at the third winter pruning with two fruit spurs 
 of two buds each and one fruit spur of one bud, five fruit buds in all. 
 
 If these five fruit buds all produce vigorous shoots during the 
 following summer, they will supply five canes of fruit wood which can 
 be used to form five fruit spurs at the following winter priming, which 
 will be about the normal increase necessary. Some of these fruit buds, 
 however, may produce weak shoots or shoots SO badly placed that they
 
 86 UNIVERSITY OF CALJFORNIA EXPERIMENT STATION 
 
 would spoil the shape of the head if used for spurs. Other shoots, 
 however, will be produced from base, secondary, and adventitious buds 
 which, while less fruitful, can be used to form spurs for the starting 
 of new arms. 
 
 Fig. 51. Seven-year-old Carignane vine with fully developed vase-formed 
 head. 
 
 Fig. 49 shows a vine after the fourth winter pruning which had 
 developed from a vine similar to that shown in Fig. 48 A. From the 
 three fruit spurs left the previous year four canes have been chosen 
 for the fruit spurs of this year. The old spur on the left has furnished 
 two new spurs and the two old spurs at the right, each one new spur.
 
 BULLETIN 241-246 
 
 VINE PRUNING IN CALIFORNIA 
 
 87 
 
 The pruner, judging that the vine is sufficiently vigorous to stand more 
 wood, has formed two spurs from water sprouts which, though not 
 likely to produce much fruit the first season, will supply fruit wood 
 for the following year. The result is a very well shaped vine with six 
 almost perfectly balanced spurs. These spurs will develop into per- 
 manent arms, some of them furnishing finally two or three. 
 
 Fig. 52. Nine-year-old Carignane vine with well formed arms. 
 
 Fig. 50 shows a high-headed vine of the same age. It has five spurs, 
 of which four are fruit spurs and one a spur of sterile wood left to 
 shape the vine. The two more or less horizontal spurs on the right 
 will bear fruit the following autumn and will be removed entirely at 
 the following winter pruning, as they are badly placed. The arms of 
 the vine will then be developed from the three upright spurs, which 
 are excellently placed.
 
 88 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 Each year thereafter the same process must be followed. First, 
 enough fruit spurs, as well placed as possible, must be left to produce 
 the crop. Second, on most vines, supplementary spurs of sterile wood 
 must be left to supply more arms where they are needed, and finally, 
 when the full complement of arms has developed, to supply new arms 
 to replace those which have become too long or are otherwise defective. 
 
 Fig. 51 shows a fully formed Carignane vine with six well placed 
 and well shaped arms. Such a vine will probably not need a larger 
 number of arms, but care must be taken that none of those which it has 
 become too long. This is the stage at which provision should be made 
 for replacing arms when they threaten to become too long. The arm 
 on the left will in two or three years extend too far from the head and 
 will be in danger of being broken off. This year, therefore, a replacing 
 spur should be left as near the head of the vine as possible. Such a 
 spur can be formed from the upright water sprout which can be seen 
 growing out of the three-year-old wood of the arm. One or two fruit 
 spurs can be formed from the two fruit canes above this. After these 
 fruit spurs have borne their crop the arm can be cut back to the re- 
 placing spur, which by that time will have furnished the necessary 
 fruit wood. This cutting back to shorten or replace the arm may be 
 done at the following or some subsequent winter pruning, according 
 to the way in which the growth develops. 
 
 Sometimes it is difficult to find water sprouts in suitable positions 
 for replacing spurs. This may be due to weakness of the vines, which 
 are able only to develop shoots on the fruit spurs and have no surplus 
 vigor to force out dormant buds on the older wood. This difficulty 
 can be met by shorter pruning. If an arm is too long, and at the same 
 time weak, it should be pruned to very short spurs. This will tend 
 to force water sprouts to start from the older wood near the base of 
 the arm. 
 
 The absence of water sprouts at the winter pruning may also be 
 due to their having been removed during the summer. When water 
 sprouts are removed the need of replacing wood should always be kept 
 in mind and one vigorous, well placed water sprout left near the base 
 of every long arm. 
 
 Fig. 52 shows an old Carignane vine in which this periodical short- 
 ening and replacing of the arms has been done systematically. The 
 near side of the vine is nearly bare of arms. At the previous winter 
 pruning a replacing spur was left right in the head of the vine on the 
 near side. This produced a cane which is utilized this year as a fruit 
 spur and which will develop into an arm. Another similar arm is 
 being developed this year from a water sprout growing out of the old 
 wood at the left.
 
 BULLETIN 241-246 yiNE PRUNING IN CALIFORNIA 89 
 
 Fig. 53 shows an old vineyard in which the vines have been kept 
 in good form, though the heads are a little too low. 
 
 Fan-Shaped Vines. With all headed vines the treatment up to 
 the stage represented by Figs. 39, 40, and 41 is the same except for 
 the variations in the height of the head. At the third winter pruning, 
 however, the formation of the head commences, and the pruner de- 
 termines whether it shall be vase-formed or fan-shaped. The pro- 
 duction of a vase-formed head has already been described. 
 
 At the third winter pruning the vine should be pruned to two 
 spurs, as shown in Fig. 48 B. More vigorous vines should not be given 
 more spurs, as in Figs. 47 and 48 A, but the spurs should be made 
 
 Fig. 53. Vineyard of fifteen-year-old Carignane vines with low medium 
 trunks and vase-formed heads. 
 
 longer, with four, five, or even six eyes in some cases. This is in order 
 to obtain some fruit, which might not be obtained from long pruning 
 varieties by leaving many spurs. With extremely vigorous vines one 
 fruit cane may be left at this pruning. The wires of the trellis should 
 be put up this year, if this has not already been done. 
 
 Figs. 54 and 55 illustrate the second step in the production of a 
 fan-shaped head. This form of head is used only for trellised vines 
 and long-pruned varieties. The formation of the head and the man- 
 agement of the fruit canes are therefore conveniently discussed to- 
 gether. 
 
 By comparing the pruned vine, Fig. 55, with the unpruned, Fig. 54, 
 the method of priming will be made clear. 8 The unpruned vine shows 
 two arms, the spurs of the previous year, from one of which have 
 grown three vigorous canes and from the other two somewhat less 
 
 3 By mistake the photograph from which Fig. 55 was made was reversed, so 
 that the right side of Fig. 54 corresponds tQ the left side of Fig. 55.
 
 90 
 
 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 vigorous. The pruned vine shows a complete unit, that is. a fruit 
 cane with its accompanying renewal spur on the vigorous side and a 
 spur for the production of fruit wood for the following year on the 
 other side. If the vine had been more vigorous, two complete units 
 would have been left and one or two extra spurs. 
 
 Fig. 54. Before pruning. 
 
 Fig. 55. After pruning. 
 
 As the form of the vine is determined by the renewal spurs, special 
 attention should be paid to their position. In this case, the middle 
 cane on one arm and the lower cane on the other have been used for 
 renewal spurs. This brings them both to the same height above the 
 ground and determines the place of the permanent arms. The next 
 year each of these spurs will furnish a fruit cane and one or two re- 
 newal spurs. The arms will thus in two or three years be increased
 
 BULLETIN 241-246 
 
 VINE PRUNING IN CALIFORNIA 
 
 91 
 
 to four, or, with very large vines, to six. These spurs should be chosen 
 as nearly as possible in the plane of the trellis, that is, they should not 
 project out sideways. Figs. 24 and 57 show vines of this kind of full 
 size and in full bearing. 
 
 The fruit canes also should be as nearly as possible in the direction 
 of the trellis, though this is not so important, as they can be bent over 
 to the wire when tied up, and in any case they are removed the next 
 year. 
 
 Fig. 56 shows a trellised vineyard of Sultanina. The vines are 
 somewhat irregular and proper care has not been exercised in the 
 choice of fruit canes and renewal spurs. Water sprouts have in some 
 instances been used for fruit canes, and lack of care in the selection 
 
 Fig. 56. Trellised vineyard of Sultanina. Pruning defective. 
 
 of renewal spurs is responsible for the awkward, ungainly arms. A 
 vineyard such as the one shown will not only not bear so large a crop 
 but will cost twice as much to prune as one in which the vines are kept 
 in the proper shape. 
 
 Fig. 57 shows the crop on a trellised Sultanina pruned by the 
 system under discussion. It shows the regular open distribution of 
 the grapes, all at about the same distance from the ground. Such 
 grapes develop and ripen equally and perfectly. 
 
 Double-Headed Vines. : Some growers attempt to arrange the arms 
 of their vines in two stages, one above the other, forming double-headed 
 or two-crowned vines. The method is applied to both vase-formed and 
 trellised vines. It is open to the same criticisms as the vertical cordon, 
 the chief of which is that it cannot be maintained permanently. The
 
 92 
 
 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION
 
 BULLETIN 241-246 
 
 VINE PRUNING IN CALIFORNIA 
 
 93 
 
 lower head or ring of arms finally becomes weak and fails to produce 
 wood. 
 
 A double crown can be maintained in trellised vineyards, and has 
 some advantages, the chief of which is that it makes it easier to keep 
 the vine in the single plane and to prevent arms getting into the inter- 
 rows. Fig. 58 illustrates a method of starting a double crown in a 
 trellised vineyard. The vine represented is four or five years old. 
 Finally it will have two full units on each side. The double trunk is 
 
 Fig. 58. Trellised vine with double head. 
 
 not necessary, and is, in fact, a disadvantage, as one trunk has a ten- 
 dency to grow at the expense of the other. 
 
 Vertical and Bo-wed Canes. Figs. 59 and 23 A show long-pruned 
 vines in which the fruit canes have been tied vertically to a tall stake. 
 This is a method used commonly in many vineyards. The unit of 
 pruning is the same as in the method just described, consisting of a 
 fruit cane and a renewal spur. The framework of the vine consists 
 of a trunk of medium height, with a vase-formed head consisting of 
 three or four arms. The defects of this system have been pointed out 
 on pages 59 and 60.
 
 94 
 
 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 It is used with fair success with seedless Sultanas and with some 
 wine grapes such as Colombar, Semillon, Cabernet, and Reisling, in 
 
 Fig. 59. Vine with vertical caues. 
 
 the hands of skillful pruners. The results with Sultanina are very 
 unsatisfactory. Fig. 60 shows a vineyard of this variety.
 
 BULLETIN 241-246 yiNE PRUNING IN CALIFORNIA 95 
 
 By this method, on most of the vines, the fruit canes start from 
 high up near the middle of the stake, and are therefore too short for 
 the best results. The canes which start from low down are in most 
 cases suckers, and therefore of little value for fruit bearing. 
 
 Fig. 23 B shows a vine with bowed canes. The method of pruning 
 is exactly the same as in the method just described. The bowing of 
 the canes, however, overcomes some of the defects of that method. It 
 is used regularly in many wine-grape vineyards of the cooler regions. 
 It is unsuited for very vigorous vines in rich soil. 
 
 Vertical Cordons. In head pruning the treatment of young vines 
 up to the second or third winter pruning is identical for all systems. 
 
 Fig. 60. Vineyard with vertical fruit canes. Pruning defective. 
 
 In cordon pruning the treatment for the first and second prunings is 
 also the same. That is, the vine is cut back to two buds near the level 
 of the ground until a cane sufficiently long to serve for the formation 
 of the trunk is obtained. 
 
 In the vertical cordon the trunk is three to four feet long, instead 
 of one to two, as in head pruning. This makes it necessary to have a 
 longer and more vigorous cane to start with. It may require a year 
 longer to obtain this. That is to say, at the end of the second season's 
 growth many vines will not have a single cane sufficiently developed 
 to give the necessary three and one-half feet of well ripened wood and 
 properly developed buds. At the second winter pruning, therefore, it 
 will often be necessary to cut the vine back to two buds, as at the first 
 winter pruning. 
 
 Finally a cane of the required length will be obtained. The vine 
 is then formed as already described for the second winter pruning of
 
 96 
 
 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 headed vines, except that the cane is left longer. This cane is then 
 tied to the stake, and at the end of the following year we have a vine 
 like that shown in Fig. 61. 
 
 Fig. 61. Vertical cordon, young vine unpruned. 
 
 When such a vine is pruned spurs are left at intervals along the 
 trunk, as shown in Fig. 62. Each of these spurs is a fruit spur and is 
 also the commencement of an arm. The future treatment of these arms 
 is the same as that of the arms in head pruning. 
 
 Fig. 63 shows a six-year-old Emperor vineyard pruned in this way. 
 It is in excellent condition, but cannot long be kept so. As the vines
 
 BULLETIN 241-246 yiNE PRUNING IN CALIFORNIA 97 
 
 grow older it becomes more and more difficult to obtain satisfactory 
 growth on the lower spurs. Finally, the whole growth of the vine is 
 concentrated at the top and instead of a cordon we simply have an 
 inconveniently high headed vine. 
 
 Figs. 64 and 65 show an old Emperor vine before and after pruning. 
 It was started as a vertical cordon, but has finally developed into the 
 
 Fig. 62. Vertical cordon, young vine pruned. 
 
 form described. Such a vine has none of the advantages of a cordon 
 and is inferior to a headed vine of moderate height. 
 
 Fig. 66 shows a double vertical cordon. This has no advantage 
 over the single cordon and all its disadvantages. It is, moreover, more 
 Jroublesome and costly to prune and the bunches are more difficult to 
 gather without injury. More than two stems are sometimes grown, 
 which increases these difficulties and defects. 
 
 Horizontal Cordons. During the first two or three years vines 
 which are to be given the form of horizontal cordons are treated ex-
 
 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION 
 
 Fig. 63. Vineyard of vertical cordons. 
 
 Figs. 64 and 65. Ultimate form of a vertical cordon, pruned and unpruned, 
 defective.
 
 BULLETIN 241-246 yiNE PRUNING IN CALIFORNIA 99 
 
 actly as for vertical cordons ; that is, they are pruned back to two buds 
 each winter and the growth forced by disbudding into a single cane 
 during the summer. 
 
 As soon as a well ripened cane of the required length is obtained 
 it is tied to a wire stretched horizontally along the row at from twenty 
 to twenty-four inches from the ground. 
 
 For this system of pruning the rows should be twelve to fifteen 
 feet apart and the vines six, seven, or eight feet apart in the rows. 
 As the cordon or trunk of each vine should reach the next vine it will 
 have to be six to eight feet long. The best shape is obtained when, the 
 trunk is all formed one year from a single cane (see Fig. 67a). It is 
 easier and sometimes necessary, however, to take two years for the 
 formation of the trunk (see Fig. 67&). In any case, the cane first tied 
 down should reach at least half way to the next vine. The following 
 year a new cane from the end of this should be used to complete the 
 full length of the trunk. 
 
 In attaching the cane to the wire it must be bent over in a gentle 
 curve and care taken not to break or injure it. The proper form of 
 the bend is shown in Figs. 67 and 68 and by the vine at the left side 
 of Fig. 69. Sharp bends such as those shown by the vines in Fig. 70 
 and on the right of Fig. 69 should be avoided. 
 
 The cane should be placed on top of the wire, but should not be 
 twisted around it. The end should be tied firmly and the rest of the 
 cane supported by strings tied loosely in order to avoid girdling when 
 the cane grows. 
 
 In the following spring most of the buds on a good cane will start. 
 If the cane is short jointed some of the shoots should be removed and 
 only those shoots allowed to develop which are conveniently situated 
 for permanent arms. If the vines are to be short pruned, the arms 
 should be developed every eight to twelve inches from a few inches 
 beyond the bend to the extreme end. For long pruning the arms 
 should be farther apart, twelve to twenty inches. Shoots starting from 
 the upper side of the cane and growing vertically upward are to be 
 preferred. Shoots starting from the lower side should be rubbed off 
 as soon as they start. As the shoots develop the strongest should be 
 pinched, repeatedly if necessary. This will tend to force the growth 
 of the weaker shoots and to equalize the vigor of all. 
 
 As the shoots become long enough they should be tied to the top 
 wire. This will insure their retaining their position on the upper side 
 of the cordon. Most of these shoots will bear grapes, and if they are 
 not tied to the wire the weight of the grapes will bend them towards 
 the ground and turn the cane over. The result will be that the next
 
 100 
 
 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 year the canes will be all on the under side of the cordon and the 
 cordon will be completely bare on top. 
 
 Fig. 66. Vertical cordon with double trunk, defective. 
 
 Such a cordon will always be defective. The arms grow towards 
 the ground and bring the grapes too low and in contact with the soil. 
 The bare top of the cordon will be exposed to the sun, which will 
 weaken it and render it subject to fungous decay. This is what has 
 happened to the defective cordons shown in Figs. 70 and 71.
 
 BULLETIN 241-246 
 
 VINE PRUNING IN CALIFORNIA 
 
 101 
 
 At the end of the season the vines should have produced a fair crop 
 and there should be from five to ten canes growing on each cordon of 
 full length. These canes are then pruned back to two or three buds, 
 or a little longer for long-pruned varieties. 
 
 There is still danger of the turning over of the cordon during the 
 following season. This must be provided for by tying some of the 
 spurs to the upper wire. One at the end, one near the middle, and 
 
 Fig. 67. Forming the cordon. Second winter pruning. 
 
 one near the bend are sufficient. In cases where short spurs are used 
 three of them must be left long enough to reach the wire and the extra 
 buds cut off either at the winter pruning or when they start in the 
 spring. In subsequent years the cordon will be heavy and rigid enough 
 to be safe from turning over. 
 
 Fig. 68. Completed cordon (unilateral). Half -long pruning. 
 
 During the following spring and summer the vines should be care- 
 fully suckered and unnecessary water sprouts removed. Any shoots 
 coming from the lower side of the cordon should be removed early to 
 strengthen the growth in the shoots on the upper side. Neglect of this 
 precaution is shown by the vines in Figs. 70 and 71. Such vines are 
 apt to become dry or decayed on the upper side. At the end of this 
 year, which should be the fourth or fifth from planting at the latest, 
 the cordon will be fully formed and the final style of pruning can be 
 applied. A short-pruned cordon vine is shown in Fig. 26. The arms 
 and spurs are a little too numerous and too close together. If this
 
 102 
 
 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 vine required the number of buds shown it would have been better to 
 have left the fruit spurs longer and to have left fewer and shorter wood 
 spurs. 
 
 Fig. 68 shows a cordon pruned half long. This is an excellent 
 system for Malaga, Emperor, and Cornichon when growing in very 
 fertile soil. It gives the half-long fruit canes which these varieties 
 need to produce good crops. 
 
 Fig. 69 shows a well formed cordon in full bearing. The vine is 
 
 Fig. 69. Unilateral horizontal cordon; var. Semillon. 
 
 Semillon grafted on St. George and is pruned short. The Semillon is 
 a variety which usually requires long pruning, but the combined effects 
 of grafting on resistant stock and horizontal cordon pruning have in- 
 creased its fertility so that a sufficient crop is obtained from short 
 spurs. If such a vine were pruned long it would quickly exhaust itself, 
 except in the richest soil. 
 
 Fig. 70 shows an old Semillon cordon with several defects. The 
 bend is too short and the growth of cane is all from the lower side. 
 The half-long canes in this case will not exhaust the vine because most 
 of them are water sprout canes and will bear little. 
 
 Fig. 71 gives a view of the vineyard in which the vine of Fig. 70 
 grew. Little or no benefit is obtained from cordons handled in this 
 way.
 
 BULLETIN 241-246 V INE PRUNING IN CALIFORNIA 103 
 
 Fig. 72 shows a vineyard of Colombar, illustrating a bilateral cordon. 
 With vines at the same distance apart, each cordon is only half the 
 length of a unilateral cordon. It is a little easier to establish but more 
 difficult to keep in good form. One branch tends to become stronger 
 than the other and in windy situations the branch growing toward the 
 prevailing wind is more subject to injury. 
 
 Renovation of Imperfect or Misshapen Vines. The pruner with 
 definite ideas who properly handles his vines from the beginning can, 
 in most cases, bring them into the required shape with comparative 
 
 Fig. 70. Defective cordon. 
 
 ease. Often, perhaps usually, he has to deal with vines which have 
 some more or less serious fault. They may be misshapen owing to 
 defective pruning, or otherwise- imperfect, owing to mechanical in- 
 juries, or as the result of frost, fungi, or insect pests. 
 
 If the vines are young, the defects can often be overcome and the 
 vine given a proper form very easily. 
 
 Fig. 73 shows a vine at the end of the year after tying up. Most 
 of the growth has gone into a cane near the base and the growth from 
 the top buds has been poor. This condition is likely to occur when a 
 small or imperfectly ripened cane has been used from which to at- 
 tempt to form a trunk. There are three possible ways of pruning this 
 vine. First, the two small canes at the top may be cut back to form 
 spurs and all other canes removed. This will give a vine with the head 
 at the right height, but all the best wood has been cut off. It will 
 result in four large wounds on the trunk, and the vine will require a
 
 104 
 
 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION 
 
 great deal of attention during the following growing season, as water 
 sprouts will be numerous and vigorous on the lower and healthier 
 portion of the vine. Moreover, the attempt to force the growth into 
 the weak top will delay the development of the vine and even result 
 in a permanently weak top. 
 
 Second, two or three of the canes about the middle of the trunk 
 may be cut back to spurs and the rest removed, including the whole 
 
 -Detective 
 
 top and the largest cane at the bottom. This will give a healthier and 
 stronger vine, but the head will be too low. 
 
 Third, a new trunk may be started from the strong cane near the 
 bottom and the whole growth above removed, as shown in Fig. 74. 
 This preserves the strongest cane, on which most of the energies of the 
 vine were expended during the preceding season, only one large wound 
 is made, and all the defective and dwarfed parts of the vine are re- 
 moved. The formation of the head is deferred one year, but the vine 
 will have a stronger, healthier, and better formed trunk, and will 
 probably bear as much the following year as if pruned in either of the 
 other ways. 
 
 In any vineyard many of the vines, in some, most of them, will show 
 imperfections or abnormalities of a similar nature. No general rule 
 of treatment can be given; each vine is a separate problem. The
 
 BULLETIN 241-246 yiNE PRUNING IN CALIFORNIA 105 
 
 primer should endeavor to choose that method in each case which will 
 finally and most quickly give him a vine of the desired form while 
 utilizing as much as practicable the best and most vigorous parts of the 
 vine and making as few and as small wounds as possible. 
 
 As the vines become older it becomes increasingly difficult to over- 
 come defects of formation. The disadvantage of a low head may be 
 in part avoided by gradually lengthening the arms and giving them a 
 more vertical direction. An ill-formed head may be improved by re- 
 moving badly placed arms and developing new arms where needed. 
 
 The trunks of many old vines are so defective that little improve- 
 
 Fig. 72. Vineyard of horizontal cordons, bilateral. 
 
 ment can be obtained by these means. It is possible and occasionally 
 profitably to completely renew the. trunks of such vines. This can be 
 done by developing a new trunk from a strong cane originating at or 
 below the surface of the ground and then cutting away the old trunk. 
 This method has the same defect as the grafting of old vines. It 
 leaves a large wound where the old stump was removed, a wound which 
 can never heal and which finally allows the entrance of wood-rot fungi. 
 Such renewed vines, however, 'may last as long as if the old decayed 
 trunk had been left or longer. They will also be more fruitful and 
 easier to handle properly. The change can be made without the loss 
 of a crop that occurs in grafting. If the stumps are large, the expense 
 of sawing them off is considerable.
 
 106 
 
 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 Choice of a System. In choosing a system we must consider care- 
 fully the characteristics of the particular variety we are growing. A 
 variety which bears only on the 1 upper buds must be pruned "long," 
 that is, must be given fruit canes. It should be noted that many 
 varieties, such as Petite Sirah, which will bear with short pruning when 
 grafted on resistant roots, require fruit canes when growing on their 
 own roots. In general, grafted vines require shorter pruning than 
 
 Fig. 73. Young vine with imperfect top. 
 
 ungrafted. If pruned the same, the grafted vines may overbear and 
 quickly exhaust themselves. This seems to be the principal reason for 
 the frequent failure of Muscat vines grafted on resistant stock. The 
 cultural conditions also affect the vine in this respect. Vines made 
 vigorous by rich soil, abundant moisture, and thorough cultivation 
 require longer pruning than weaker vines of the same variety. 
 
 The normal size of the bunch is als.o of importance. This size will 
 vary from one-quarter of a pound to two or three pounds. It is diffi- 
 cult to obtain a full crop from a variety whose bunches are very small, 
 without the use of fruit canes. Spurs will not furnish enough fruit 
 buds without crowding them inconveniently. On the other hand, some 
 shipping grapes may bear larger crops when pruned long, but the 
 bunches and berries may be too small for the best quality.
 
 BULLETIN 241-246 
 
 VINE PRUNING IN CALIFORNIA 
 
 107 
 
 The possibilities of development vary much with different varieties. 
 A Mission or Flame Tokay may be made to cover a quarter of an acre 
 and develop a trunk four or five feet in circumference. A Zinfandel 
 vine under the same conditions would not reach a tenth of this size in 
 the same time. Vines in a rich valley soil will grow much larger than 
 on a poor hillside. The size and shape of the trunk must be modified 
 accordingly and adapted to the available room or number of vines to 
 the acre. 
 
 Fig. 74. Pruning to renew imperfect top of vine of Fig. 73. 
 
 The shape of the vine must be such as to protect it as much as 
 possible from various unfavorable conditions. A variety susceptible 
 to oidium, like the Carignane, must be pruned so that the fruit and 
 foliage are not unduly massed together. Free exposure to light and 
 air are a great protection in this respect. The same is true for varieties 
 like the Muscat, which have a tendency to "coulure" if the blossoms 
 are too moist or shaded. In frosty locations a high trunk will be a 
 protection, as the air is always colder close to the ground. 
 
 The qualities required in the crop also influence our choice of a 
 pruning system. With wine grapes, even, perfect ripening and full 
 flavor are desirable. These are obtained best by having the grapes at 
 a uniform height from the ground and as near to it as possible. The
 
 108 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 same qualities are desirable in raisin grapes, with the addition of large 
 size of the berries. With shipping grapes the size and perfection of 
 the berries and bunches are the most essential characteristics. The 
 vine, therefore, should be so formed that each bunch hangs clear, free 
 from injurious contact with canes or soil and equally exposed to light 
 and air. 
 
 The maximum returns in crop depend on the early bearing of 
 young vines, the regularity of bearing of mature vines, and the long- 
 evity of the vineyard. These are insured by careful attention to all 
 the details of pruning, but are possible only when the vines are given a 
 suitable form. 
 
 The running expenses of a vineyard depend in a great measure on 
 the style of pruning adopted. Vines of suitable form are cultivated, 
 pruned, and the crop gathered easily and cheaply. This depends also 
 both on the form of vine adopted and on care in details. 
 
 It is impossible, therefore, to state for any particular variety or 
 any particular location the best style of pruning to be adopted. All 
 that can be done is to give the general characteristics of the variety 
 and to indicate how these may be modified by grafting, soil, or climatic 
 or other conditions. 
 
 The most important characteristic of the variety in making a choice 
 of a pruning system is whether it normally or usually requires long 
 or half-long pruning. With this idea, the principal grapes grown 
 in California, together with all those grown at the Experiment Station 
 on which data exist, have been divided into five groups in the following 
 list: 
 
 1. Varieties Which Require Long Pruning Under All Conditions. 
 Clairette blanche, Corinth white and black, Seedless Sultana, Sultanina 
 white (Thompson's Seedless) and rose. 
 
 2. Varieties Which Usually Require Long Pruning. Bastardo, 
 Boal de Madeira, Chardonay, Chauche gris and noir, Colombar, 
 Crabbe's Black Burgundy, Dizmar, Gamais, Kleinberger, Luglienga, 
 Marsanne, Marzemino, Merlot, Meunier, Muscadelle de Bordelais, Neb- 
 biolo, Pagadebito, Peverella, Pinots, Rieslings, Rish Baba, Robin noir, 
 Rulander, Sauvignon blanc, Semillon, Serine, Petite Sirah, Slanca- 
 menca, Steinschiller, Tinta Cao, Tinta Madeira, Trousseau, Verdelho, 
 Petit Verdot, Walchriesling. 
 
 3. Varieties Which Usually Require Short Pruning. Aleatico, 
 Aligote, Aspiran, Bakator, Bouschets, Blaue Elbe, Beba, Bonarda, 
 Barbarossa, Catarattu, Charbono, Chasselas, Durif, Freisa, Frontig- 
 nan, Furmint, Grand noir, Grosseblaue, Green Hungarian, Malmsey,
 
 BULLETIN 241-246 VINE PRUNING IN CALIFORNIA 109 
 
 Mantuo, Monica, Mission, Moscatello fino, Mourisco branco, Mourisco 
 preto, Negro amaro, Palomino, Pedro Zumbon, Perruno, Pizzutello di 
 Roma, Black Prince, West's White Prolific, Quagliano, Rodites, Rozaki, 
 Tinta Amarella, Vernaccia bianca, Vernaccia Sarda. 
 
 4. Varieties Which Require Short Pruning Under All Conditions. 
 Aramon, Burger, Black Morocco, Mourastel, Muscat of Alexander, 
 Napoleon, Picpoule blanc and noir, Flame Tokay, Ugni blanc, Verdal, 
 Zinfandel. 
 
 5. Varieties of Table Grapes Which Usually Require Half-Long or 
 Cordon Pruning. Almeria (Ohanez), Bellino, Bermestia bianca and 
 violacea, Cipro nero, Dattier de Beirut, Cornichon, Emperor, Black 
 Ferrara, Malaga, Olivette de Cadenet, Pis-de-Chevre blanc, Schirad- 
 zouli, Zabalkanski. 
 
 These lists must not be taken as indicating absolutely for all cases 
 how these varieties are to be pruned. They simply indicate their 
 natural tendencies. Certain methods and conditions tend to make 
 vines more fruitful. Where these occur shorter pruning than is indi- 
 cated may be advisable. On the other hand, other methods and con- 
 ditions tend to make the vines vigorous at the expense of fruitfulness. 
 Where these occur longer pruning may be advisable. 
 
 The more usual factors which tend toward fruitfulness are : 
 
 Grafting on resistant vines, especially on certain varieties such as 
 those of Riparia and Berlandieri ; 
 
 Old age of the vines ; 
 
 Mechanical or other injuries to any part of the vine ; 
 
 Large development of the trunk, as in the cordon systems. 
 
 The more usual factors which tend toward vigor at the expense of 
 fruitfulness are : 
 
 Rich soil, especially large amounts of humus and nitrogen ; 
 
 Youth of the vines ; 
 
 Excessive irrigation or rainfall (within limits). 
 
 In deciding what system of pruning to adopt, all these factors, 
 together with the nature of the vine and the uses to which the fruit is 
 to be put, must be considered. It is best when the vineyard is started 
 to err on the side of short pruning. While this may diminish slightly 
 the first one or two crops, the vines will gain in vigor and the loss will 
 be made up in subsequent crops. If the style of pruning adopted 
 results in excessive vigor of the vines, it should be gradually changed 
 in the direction of longer pruning with the object of utilizing this 
 vigor in the production of crop.
 
 110 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 
 
 This change should be gradual, or the risk is run of injuring the 
 vitality of the vines by one or two excessively heavy crops. Finally, 
 each year the condition of the individual vine should determine the 
 kind of pruning to be adopted. If the vine appears weak, from what- 
 ever cause, it should be pruned shorter or given less spurs or fruit 
 canes than the year before. On the contrary, if it appears unneces- 
 sarily vigorous, more or longer spurs or fruit canes should be left. 
 Every vine should be judged by itself. It is not possible to give more 
 than general directions for the pruning of the whole vineyard. It 
 cannot be well pruned unless the men who do the actual pruning 
 understand their work and are capable of using sufficient judgment to 
 properly modify their methods for each individual vine.
 
 000 734 727 1 
 
 STATION PUBLICATIONS AVAILABLE FOR FREE 
 
 No. 
 185. 
 
 251. 
 
 253. 
 
 261. 
 262. 
 
 263. 
 266. 
 
 267. 
 268. 
 270. 
 
 271. 
 272. 
 273. 
 
 274. 
 275. 
 
 276. 
 278. 
 279. 
 280. 
 
 282. 
 
 283. 
 285. 
 286. 
 288. 
 
 No. 
 
 70. 
 
 76. 
 82. 
 
 113. 
 114. 
 115. 
 126. 
 127. 
 128. 
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 131. 
 135. 
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 138. 
 139. 
 
 143. 
 
 144. 
 148. 
 152. 
 
 153. 
 154. 
 
 155. 
 156. 
 157. 
 158. 
 159. 
 160. 
 164. 
 
 BULLETINS 
 
 No. 
 
 Report of Progress in Cereal Investiga- 290. 
 
 tions. 
 
 Utilization of the Nitrogen and Organic 299. 
 
 Matter in Septic and Imhoff Tank 300. 
 
 Sludges. 301. 
 Irrigation and Soil Conditions in the 
 
 Sierra Nevada Foothills, California. 302. 
 Melaxuma of the Walnut, " Juglans regia." 
 
 Citrus Diseases of Florida and Cuba 303. 
 
 Compared with Those of California. 304. 
 Size Grades for Ripe Olives. 
 
 A Spotting of Citrus Fruits Due to the 308. 
 
 Action of Oil Liberated from the Rind. 
 Experiments with Stocks for Citrus. 
 Growing and Grafting Olive Seedlings. _ 309. 
 A Comparison of Annual Cropping, Bi- 
 ennial Cropping, and Green Manures 310. 
 
 on the Yield of Wheat. 311. 
 
 Feeding Dairy Calves in California. 312. 
 
 Commercial Fertilizers. 313. 
 
 Preliminary Report on Kearney Vine- 316. 
 
 yard Experimental Drain. 317. 
 
 The Common Honey Bee as an Agent in 318. 
 
 Prune Pollination. 319. 
 
 The Cultivation of Belladonna in Cali- 320. 
 
 fornia. 321. 
 
 The Pomegranate. 322. 
 
 Grain Sorghums. 323. 
 Irrigation of Rice in California. 
 
 Irrigation of Alfalfa in the Sacramento 324. 
 
 Valley. 
 
 Trials with California Silage Crops for 325. 
 
 Dairy Cows. 
 
 The Olive Insects of California. 
 
 The Milch Goat in California. 326. 
 
 Commercial Fertilizers. 327. 
 Potash from Tule and the Fertilizer 
 
 Value of Certain Marsh Plants. 
 
 Observations on the Status of Corn 
 
 Growing in California. 
 Hot Room Callusing. 
 The Common Ground Squirrels of 
 
 California. 
 
 Correspondence Course* m Agriculture. 
 Increasing the Duty oi Water. 
 Grafting Vinifera Vineyards. 
 Spraying for the Grape Leaf Hopper. 
 House Fumigation- 
 Insecticide Fo-mulas. 
 The Control of Citrus Insects. 
 Cabbage Growing in California. 
 Spraying /or Control of Walnut Aphis. 
 Official Tests of Dairy Cows. 
 Wood Decay in Orchard Trees. 
 The Silo in California Agriculture. 
 The Generation of Hydrocyanic Acid Gas 
 
 \n Fumigation by Portable Machines. 
 Control of Grasshoppers in Imperial 
 
 Valley. 
 
 Oidium or Powdery Mildew of the Vine. 
 "Lungworms". 
 Some Observations on the Bulk Handling 
 
 of Grain in California. 
 Announcement of the California State 
 
 Dairy Cow Competition, 1916-18. 
 Irrigation Practice in Growing Small 
 
 Fruits in California. 
 Bovine Tuberculosis. 
 How to Operate an Incubator. 
 Control of the Pear Scab. 
 Home and Farm Canning. 
 Agriculture in the Imperial Valley. 
 Lettuce Growing in California. 
 Small Fruit Culture in California. 
 
 CIRCULARS 
 
 No. 
 165. 
 
 167. 
 168. 
 
 169. 
 170. 
 
 172. 
 173. 
 174. 
 175. 
 
 176. 
 
 177. 
 178.. 
 179. 
 
 181. 
 182. 
 
 183. 
 184. 
 185. 
 
 188. 
 189. 
 190. 
 191. 
 193. 
 198. 
 201. 
 202. 
 
 The June Drop of Washington Navel 
 Oranges. 
 
 The Use of Lumber on California Farms. 
 
 Commercial Fertilizers. 
 
 California State Dairy Cow Competition, 
 1916-18. 
 
 Control of Ground Squirrels by the 
 Fumigation Method. 
 
 Grape Syrup. 
 
 A Study on the Effects of Freezes on 
 Citrus in California. 
 
 I. Fumigation with Liquid Hydrocyanic 
 Acid. II. Physical and Chemical Pro- 
 perties of Liquid Hydrocyanic Acid. 
 
 I. The Carob in California. II. Nutri- 
 tive Value of the Carob Bean. 
 
 Plum Pollination. 
 
 Investigations with Milking Machines. 
 
 Mariout Barley. 
 
 Pruning Young Deciduous Fruit Trees. 
 
 The Kaki or Oriental Persimmon. 
 
 Selections of Stocks in Citrus Propagation. 
 
 The Effects of Alkali on Citrus Trees. 
 
 Caprifigs and Caprification. 
 
 Control of the Coyote in California. 
 
 Commercial Production of Grape Syrup. 
 
 The Evaporation of Grapes. 
 
 Heavy vs. Light Grain Feeding for Dairy 
 Cows. 
 
 Storage of Perishable Fruit at Freezing 
 Temperatures. 
 
 Rice Irrigation Measurements and Ex- 
 periments in Sacramento Valley, 1914- 
 1919. 
 
 Brown Rot of Apricots. 
 
 Commercial Fertilizers. 
 
 Fundamentals of Sugar Beet Culture 
 
 under California Conditions. 
 Feeding Stuffs of Minor Importance. 
 Spraying for the Control of Wild Morning- 
 Glory within the Fog Belt. 
 The 1918 Grain Crop. 
 Fertilizing California Soils for the 1918 
 
 Crop. 
 
 Wheat Culture. 
 
 The Construction of the Wood-Hoop Silo. 
 Farm Drainage Methods. 
 Progress Report on the Marketing and 
 
 Distribution of Milk. 
 Hog Cholera Prevention and the Serum 
 
 Treatment. 
 Grain Sorghums. 
 
 The Packing of Apples in California. 
 Factors of Importance in Producing Milk 
 
 of Low Bacterial Count. 
 Control of the California Ground Squirrel. 
 Extending the Area of Irrigated Wheat in 
 
 California for 1918. 
 Infectious Abortion in Cows. 
 A Flock of Sheep on the Farm. 
 Beekeeping for the Fruit-grower and Small 
 
 Rancher or Amateur. 
 Lambing Sheds. 
 Winter Forage Crops. 
 Agriculture Clubs in California. 
 Pruning the Seedless Grapes. 
 A Study of Farm Labor in California. 
 Syrup from Sweet Sorghum. 
 Helpful Hints to H9g Raisers. 
 County .Organization for Rural Fire 
 
 Control.
 
 CIRCULARS Continued 
 
 No. 
 
 203. Peat aa a Manure Substitute. 
 
 205. Blackleg. 
 
 206. Jack Cheese. 
 
 207. Neufchatel Cheese. 
 
 208. Summary of the Annual Reports of the 
 
 Farm Advisors of California. 
 210. Suggestions to the Settler in California. 
 
 214. Seed Treatment for the Prevention of 
 
 Cereal Smuts. 
 
 215. Feeding Dairy Cows in California. 
 
 217. Methods for Marketing Vegetables in 
 
 California. 
 
 218. Advanced Registry Testing of Dairy Cows. 
 
 No. 
 
 219. The Present Status of Alkali. 
 
 220. Unfermentcd Fruit Juices. 
 
 221. How California is Helping People Own 
 
 Farms and Rural Homes. 
 
 222. Fundamental Principles of Co-operation 
 
 in Agriculture. 
 
 223. The Pear Thrips. 
 
 224. Control of the Brown Apricot Scale and 
 
 the Italian Pear Scale on Deciduous 
 Fruit Trees. 
 
 225. Propagation of Vines. 
 
 226. Protection of Vineyards from Phyl- 
 
 loxera.