UNIVERSITY OF CALIFORNIA PUBLICATIONS 
 
 COLLEGE OF AGRICULTURE 
 AGRICULTURAL EXPERIMENT STATION 
 
 BERKELEY, CALIFORNIA 
 
 VINE PRUNING IN CALIFORNIA 
 
 PART I. 
 By FREDERIC T. BIOLETTI 
 
 The native vine of California (Vitis Calif ornica). 
 
 BULLETIN No. 241 
 
 (Berkeley, CaL) 
 
 Printed at the State Printing Office, Friend Wm. Richardson, Superintendent 
 
Benjamin Ide Wheeler, President of the University. 
 
 EXPERIMENT STATION STAFF. 
 Heads of Divisions. 
 
 Thomas Forsyth Hunt, Director. 
 
 Eugene W. Hilgard, Agricultural Chemistry (Emeritus). 
 
 Edward J. Wickson, Horticulture. 
 
 Herbert J. Webber, Director Citrus Experiment Station ; Plant Breeding. 
 
 Hubert E. Van Norman, Vice-Director and Dean of the University Farm School 
 
 Dairy Management. 
 William A. Setchell, Botany. 
 Myer E. Jaffa, Nutrition. 
 
 Robert H. Loughridge, Soil Chemistry and Physics (Emeritus). 
 Charles W. Woodworth, Entomology. 
 Ralph E. Smith, Plant Pathology. 
 J. Eliot Coit, Citriculture. 
 John W. Gilmore, Agronomy. 
 Charles F. Shaw, Soil Technology. 
 
 John W. Gregg, Landscape Gardening and Floriculture. 
 Bernard A. Etcheverry, Irrigation. 
 Frederic T. Bioletti, Viticulture and Enology. 
 Warren T. Clarke, Agricultural Extension. 
 John S. Burd, Agricultural Chemistry. 
 Charles B. Lipman, Soil Chemistry and Bacteriology. 
 Clarence M. Haring, Veterinary Science and Bacteriology. 
 Ernest B. Babcock, Genetics. 
 Gordon H. True, Animal Husbandry. 
 James T. Barrett, Plant Pathology. 
 Fritz W. Woll, Animal Nutrition. 
 Burr B. Pratt, Pomology. 
 
 William G. Hummel, Agricultural Education. 
 Frank L. Peterson, Farm Mechanics. 
 David N. Morgan, Assistant to the Director. 
 Mrs. D. L. Bunnell, Librarian. 
 
 DIVISION OF VITICULTURE AND ENOLOGY. 
 
 Frederic T. Bioletti. L. Bonnet. 
 
 W. V. Cruess. A. E. Way. 
 
 F. C. H. Flossfeder. W. F. Oglesby. 
 
VINE PRUNING IN CALIFORNIA. 
 
 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 Calif ornian vine grower. Most publications in English refer to 
 methods suited to the Eastern States and to Eastern varieties or to the 
 conditions of hot-house cultivation. Foreign publications, besides being 
 more or less inaccessible, are adaptecf to conditions different from those 
 of the Pacific Slope or treat the subject so widely that the grower is at a 
 loss to choose from such a mass of material. 
 
 In 1897 the College of Agriculture published Bulletin 119, "Vine 
 Pruning," for which there was so much demand that the edition was 
 quickly exhausted. This bulletin was revised and republished in the 
 Report for 1897-98, appearing in 1900. This edition has also been 
 long exhausted. In 1907 Bulletin 193 was issued containing articles 
 on the ' ' Pruning of Young Vines ' ' and the ' ' Pruning of the Sultanina. ' ' 
 Of this, also, there remain no copies available for distribution. 
 
 Need of the Bulletin. — The demand for information on vine pruning 
 still continues and its necessity is made evident by the unsightly, de- 
 fective and unprofitable condition of many of our vineyards. 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 result 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 numer- 
 ous mistakes made in the past. 
 
 Definition. — The term pruning, both by derivation and usage, is 
 applied to various operations which consist 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 dis- 
 cussed 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 does not properly describe the various 
 operations of suckering, disbudding, water-sprouting and the attach- 
 ment of fruit canes which we do use. The word pruning, moreover, 
 
— 4 - 
 
 seems sufficient alone, as all the other operations follow and are necessi- 
 tated 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, 
 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 quantity 
 and quality, depend on many factors, of which the chief are the char- 
 acter 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 advantages. Many 
 vineyards produce less than half their proper average crop owing to 
 mistakes in pruning, and there are very few vineyards in the State 
 where both the amount and 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 most serious in its effects and 
 its removal would in most cases obviate the greatest part of the trouble 
 due to the former. 
 
 Some Results of Defective Pruning. — In order to emphasize the neces- 
 sity 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. 
 
 (b) 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) Over-bearing of weak vines. 
 
 (b) 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. 
 
 (6) Pruning, suckering. 
 
 (c) Control of diseases, oidium, vine-hopper. 
 
 (d) Gathering, trimming, sorting, culling. 
 
— 5 — 
 
 4. Shorter life of vines, due to — 
 
 (a) Pruning and cultivation wounds. 
 
 (b) Occasional over-bearing. 
 
 (c) Growth of suckers. 
 
 A young vine under average conditions in California should bear 3 
 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 defec- 
 tive 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 obtained only by carefully 
 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 prun- 
 ing adapted to a weak vine would prevent a vigorous vine from bearing 
 and waste its possibilities, while a method adapted to a vigorous 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 diminishes 
 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 following 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 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. These defects are due not 
 so much to the total weight of crop, which may not be excessive, as to 
 the excessive number of individual grapes and bunches. 
 
 Bad pruning results in uneven and improper distribution of the 
 grapes on a vine. This is particularly harmful to shipping grapes, 
 
— 6 — 
 
 resulting in uneven ripening 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 impos- 
 sible 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 suckered 
 at much less cost than irregular, misshapen vines. The control of the 
 vine-hopper is impossible and that of oidium and other diseases 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 shipping 
 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 inju- 
 ries from the implements of cultivation. These wounds and injuries 
 afford means of ingress to injurious parasites, borers of various kinds 
 and particularly of infection by black knot and wood-rot fungi. 
 Irregularity 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 vinifera. — "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 coun- 
 tries 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 varieties 
 originated in Asia and Northern Africa. The varieties are sometimes 
 spoken of as Californian grapes because they are not grown east of the 
 Rockies or to any great extent in North America outside of California. 
 They include all the varieties of vines grown in California except 
 resistant stocks and a few Labrusca or Eastern varieties such as Con- 
 
— 7 — 
 
 cord and Pierce, grown to a limited extent. This difference of species 
 between the varieties grown in the Eastern States and those grown 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 vinifcra and its varieties, like all true vines, are sarmentose 
 plants, that is, they possess long, slender, flexible trunks incapable of 
 self-support and attaching themselves by means of tendrils to trees or 
 other available support. If allowed to grow without restriction, they 
 will grow to the top of high trees in a manner similar to the Labrusca 
 vines of the Eastern States or the wild Vitis Calif ornica of the Pacific 
 States. (See cover cut and figure 1.) 
 
 In vineyards, the natural habit of the vine is modified to a remarkable 
 extent, principally by pruning. Most cultivated vinifera vines are 
 given the form of a low self-supporting shrub with a short, ri^id, ver- 
 tical 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 permanent 
 framework, consisting of root, trunk and arms, producing an annual 
 growth of shoots, leaves and fruit above ground and of rootlets 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 vines and from- three to six 
 in high. 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 functions are 
 the production of young wood and the proper distribution of leaves and 
 fruit. 
 
 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 all cases from 90 per cent to 98 per cent of all the growth is removed 
 at each pruning. 
 
— 8 — 
 
 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 
 
— 9 — 
 
 cases the usage of the majority of Californian grape growers has been 
 
 followed. 
 
 terms referring 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. 
 
 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 or 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. 
 Arms. The main divisions (when short) of the trunk or branches. 
 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. 
 (&) Replacing Spurs. Spurs left to supply growth for 
 the replacing of defective arms, 1 eye. 
 Fruit Canes. Canes from two-year-old wood left for fruit, 1^ to 6 feet 
 long. 
 
 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. 
 
— 10 — 
 
 2. During the formation of leaves. 
 Shoots. The succulent growth arising from a bud. 
 Fruit Shoots. Shoots bearing flowers. 
 Wood Shoots. 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. 
 Ca)ies. 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 growing out of two-year-old wood. 
 Sterile Wood. Canes growing out of wood older than two years. 
 
 Roots. — The pruner has little to do with the roots except when plant- 
 ing 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 practised 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. 
 
 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 matters 
 for spring growth and to hold the vine in place. The position, 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 stimuate 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 which 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. 
 
— 11 — 
 
 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 
 
 Fig. 2. Root crown of a four-year-old' vine. 
 
 irrigations, by avoiding a continually wet surface in the growing season 
 during the first two years and, when necessary, by removing the surface 
 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 
 
— 12 — 
 
 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 re-form 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 it 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.) . 
 
 In wet soil 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 and aeration 
 are most favorable and all below this point dies. In drier soil 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 cut- 
 ting and completely heal the surface. A root crown at the surface of 
 the ground is very objectionable as it is very subject to injury from 
 plow and hoe, and consequently subject to infection by black knot and 
 wood rot fungi. It also makes clean cultivation 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 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 depends 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 or 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 suffi- 
 cient 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 cor- 
 responding 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 
 
— 13 — 
 
 the arms start. At first it is more or less indefinite, the spurs from 
 which the arms finally develop being at various 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 practically the same level by the removal of ill placed arms before 
 they become large and a definite head 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 in 
 certain forms of high trellises or in covering an arbor. Where the trunk 
 is simply elongated without branching or has only two horizontal 
 
 Pig. 3. — Carignane vine firteen years old. 
 Well formed trunk, head and arms ; short spurs. 
 
 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 which bear 
 the spurs and fruit canes. They should be long enough to spread the 
 crop sufficiently 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 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. 
 
— 14 — 
 
 The arms constantly tend to become too long, and it requires skill, 
 knowledge and foresight on the part of the pruner 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. 
 
 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 .i 
 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 prun- 
 ing the number of arms is correspondingly decreased, while with long 
 or cane pruning, two to four arms are all that should be given. 
 
 Fig. 
 
 4. — Muscat vine, over fifteen years old. Trunk too short, arms too long, but head 
 
 of good form. 
 
 The arrangement of the arms depends principally on the planting 
 plan and method of cultivation. When the vines are approximately 
 equidistant in all directions and cross cultivation is practiced, the arms 
 should be arranged as symetrically as possible in ' ' vase-form. ' ' When 
 the vines are planted closer together in rows with wider "avenues" 
 between them, especially when trellised, cross cultivation is impossible. 
 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 
 
— 15 — 
 
 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, can be used for this 
 purpose. The average length of a fruit spur is two nodes giving 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 function 
 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 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 must 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 increased 
 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- 
 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 defec 
 tive 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 
 
— 16 — 
 
 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 
 
 Fig. 5. — Cross-section through vine 
 "eye" showing central main bud and 
 two or three lateral secondary buds. 
 
 should be done with sufficient frequency to avoid making the excessively 
 large wounds which would be necessary if the arms were allowed to 
 become very old and large. Spurs left to produce new arms on develop- 
 
 Fig. 6. — Cross-section through fruit 
 bud showing two embryonic blossom 
 bunches. 
 
 ing 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 
 
— 17 — 
 
 size of the bunches, which makes it difficult to obtain a sufficient number 
 from spurs to constitute a full crop. In such cases it is necessary to 
 adopt some form of long pruning, with fruit canes. A fruit cane is a 
 
 Fig. 7. — Longitudinal section of a 
 fruit bud showing an embryonic shoot 
 with embryonic leaves and blossom 
 bunch. 
 
 piece of the current year's fruit wood from one and one half to six feet 
 long. ! 
 
 Particular attention should be given that these canes consist of fruit 
 wood, that is, of canes growing out of two-year-old wood. To leave 
 
 Fig. 8. — Longitudinal section of a 
 sterile bud. 
 
 sterile wood, suckers or water-sprouts for this purpose is useless and 
 fails to utilize the vine's possibilities of bearing. 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 obtained 
 2 — bul241 
 
— 18 — 
 
 from fruit canes longer 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 injuring the vine by over-bearing. This latter 
 danger is particularly 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, consisting of a 
 main central bud with one or two smaller secondary buds within the 
 same bud scales. (See Fig. 5.) 
 
 The external appearance of all the eyes on a vine is similar. They 
 differ, however, in the important respect that some are capable of pro- 
 ducing 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. 
 
 There is no external difference in appearance between fruitful and 
 sterile buds, and the pruner has no means of determining with certainty 
 whether an eye contains the possibility of fruiting or not. He can, 
 however, tell what the relative probability of fruitfulness is with dif- 
 ferent 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. 
 Water-sprout canes and suckers, therefore, are not suitable for fruit 
 spurs or fruit canes. 
 
 The position of the eye on the cane is also of importance in judging 
 of its probability cf 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 eyes. From this point on the eyes are 
 usually equally fruitful until we reach a point where the cane is imper- 
 fectly developed or badly matured. Sterility of the lower buds makes 
 long pruning necessary. 
 
 A bud may be fruitful in varying degrees. A thoroughly fruitful 
 
— 19 — 
 
 bud of most vinifera varieties will produce on the average two bunches 
 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 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. 
 
 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 pro- 
 duce 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 dormant 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. Any 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 injuring 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 secondary buds may 
 also produce fruit but the bunches are smaller and less numerous. 
 Similar small bunches may be produced by shoots from the buds of 
 suckers or water-sprouts. Other shoots are sterile, producing only 
 tendrils in the place of fruit and are called wood shoots. 
 
 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 imperfect, a 
 
— 20 — 
 
 shoot from 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 
 
 Fig. 9. — Blossom-bearing shoot of Tokay vine. 
 
 further it produces more tendrils but not at all nodes in vinifera 
 varieties. 
 
 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 very short or may grow 
 out and form large lateral canes. Any injury to the growing tip of 
 the main shoot stimulates the production and growth of laterals. Lat- 
 erals of some varieties may produce fruit like main canes. This fruit 
 
— 21 — 
 
 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 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. The difference between the two kinds of wood varies greatly 
 
 Fig. 
 
 10. — Fruit-bearing cane of Black Morocco, showing (I) first crop, (II) 
 second crop, and (III) third crop. 
 
 with different varieties. On a Muscat or Alexandria most of the buds, 
 even on water-sprout canes, contain rudiments of blossoms, while on a 
 Sultanina they are almost always sterile. The fruitfulness of all kinds 
 of wood moreover depends on weather, soil and cultural conditions. In 
 some cases the conditions 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 pro- 
 portion 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. 
 
— 22 — 
 
 THE PRINCIPLES OF PRUNING. 1 
 
 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 of its crop are elaborated in 
 the leaves by means of the chlorophyll under the influence of sunlight. 
 The carbonic acid of the air and the 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 function- 
 ing 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 cf production and if carried too far may result 
 in starvation of the vine. 
 
 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 diminish bear- 
 ing, and, vice versa, methods w r hich diminish vigor increase bearing. 
 Failure to reckon with this fact and to maintain a proper mean between 
 the two extremes lead, on the one hand, to comparatively 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 injuring the tissues of the vines 
 or of its parts tend to diminish its vegetative vigor and, therefore, unless 
 excessive, to increase its fruitfulness. 
 
 J The second' part of this bulletin, entitled "The Practice of Pruning," is prepared 
 and will be published shortly. 
 
— 23 — 
 
 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 removal 
 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 vig- 
 orous 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 are inversely as their number, 
 if other conditions remain the same. 
 
 Thus, for example, the fewer vines to the acre, the larger eah 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 the pruning may have to be spread 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 consider 
 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. Pruning 
 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 maximum 
 amount of food material, viz, starch, sugar, cellulose and other carbo- 
 hydrates. For two or three weeks, immediately following the fall of 
 the leaves much of these substances passes rapidly downwards to 
 
— 24 — 
 
 accumulate as reserves in the roots. Later these reserves ascend again 
 slowly, to supply the above ground portions of the vine which, thougn 
 dormant, still require nutrition. In spring, during the period just 
 before and just after the starting of the buds, this upward migration 
 of reserves is more rapid and continues until the young leaves are suffi- 
 ciently 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 for 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, 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 Davis of shorter duration. 
 
 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 20th 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, when 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 tl:* injurious effects of spring frosts. In 
 one of our tests, the crop on niiit rows pruned March 13th was saved, 
 while that of twelve rows pruned November 19th and December 21st 
 was completely ruined by a frost on April 21st. Late pruning also 
 retards the blossoming though somewhat less than it does the starting. 
 Pruning 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 
 
 a Vidal, J. L. "Les reserves de la Vigne." Revue de Viticulture I, pp. 895 to 903. 
 2 Ravaz, L. "Taille hative ou Taille tardive," 1912. 
 
— 25 — 
 
 the frost having destroyed the first shoots, the only flowers and fruit 
 which appear are on buds which have started after the frost. 
 
 Vines pruned before the fall of the leaves are weakened. Otherwise 
 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 blossoming 
 may also be a factor. At Davis, 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 benefits 
 of late pruning without its inconveniences can 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 time during the winter that is 
 convenient. 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 prun- 
 ing. The base buds are said to be retarded by the length of cane above 
 them the presence of buds on the cane having no effect. 
 
 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 early. Very vig- 
 orous vines, especially in frosty locations, should be pruned late. 
 
 Amount of Pruning. — 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 pruned 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 Physiological 
 Principle No. 5, page 25.) The quality and quantity of the crop and 
 the vigor of the vine and its shoots will be influenced little, if at all. 
 
— 26 — 
 
 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, 
 page 25.) This smaller number of large shoots will produce as much 
 foliage as the larger number of small shoots on the unpruned vine and 
 the vigor of the vine is therefore not 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 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 skin which form a larger part of small berries. 
 
 We can increase the severity of the pruning, that is, diminish 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 causes 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, 
 page 24), often causing "coulure" or dropping of the blossoms without 
 "setting." The primer should endeavor, therefore, to leave just 
 enough fruit buds to furnish the number of bunches that the vine can 
 bring to perfection. 
 
 Beyond this point the crop is diminished and the vigor of the vine 
 correspondingly increased. If we prune the vine so severely that no 
 crop is produced, the vigor of the vine attains its maximum. Even 
 though we prune off all the growth of the season the vine is not weak- 
 ened, as it produces shoots from dormant and adventitious buds with 
 so much facility that the foliage produced is as great as when we leave 
 spurs with well formed buds. 
 
 Heavy winter pruning, therefore, invigorates the vine by diminishing 
 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 
 overbearing. On a mature vine of normal vigor, the primer should 
 leave the same number of spurs and fruit buds as were 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 
 
— 27 — 
 
 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 
 into building up tissues and replenishing its store of reserve food 
 materials. Any attempt to make a weak vine bear a normal crop can 
 succeed 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 invigorated 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 the 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 produce fruit by 
 being left longer whether as fruit spurs or fruit canes. 
 
 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 by weight of alcohol to one part by 
 weight of iodine. 
 
 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 indi- 
 cate 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 very fair idea of the amount of reserves 
 in the vines and is a valuable aid in determining the amount of prun- 
 ing 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 required 
 will depend on the form aimed at and on the more or less favorable 
 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 
 
— 28 — 
 
 of consideration altogether except in so far as it affects the attainment 
 of the desired form. Vines which are so pruned 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 maintenance 
 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 bear- 
 ing, 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. 
 
 Fig. 11. — Unit of short pruning. 
 
 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 Californian 
 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 treat- 
 ment 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, repre- 
 senting 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 Ci). Near the base of the arm is shown a single water-sprout 
 (WS) 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. 
 
— 29 -^ 
 
 In priming such an arm, one of the canes growing out of the spur of 
 the previous year ($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, 
 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 (0) three or four inches. 
 
 Fig. 12. — Unit of long pruning. 
 
 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. 
 
 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 
 while the fruit spur from cane C will bear a crop and the replacing 
 spur B will produce fruit wood for the following year. 
 
 The cane chosen (C) is cut at a, 1), or d, leaving a fruit spur of one, 
 two or three fruit buds and the cane, Ci, removed entirely by a cut at /. 
 The more vigorous the variety and the particular cane, the more buds 
 
— 30 — 
 
 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. 
 
 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, F2, with its renewal spur, Si. 
 
 In the illustration, #2 represents the renewal spur of two years 
 previous. On it was left a fruit cane F2, which has produced the crop 
 of the previous season and a renewal spur, Si, which has produced fruit 
 wood for the present season. 
 
 In pruning, the fruit cane, F2, is removed entirely at g. The upper 
 cane, C, of the renewal spur, Si, is used for a new fruit cane and short- 
 ened to about / for half long and to about /1 for long pruning. The 
 lower cane, Ci, is cut back at a to form a renewal spur, S, which will 
 produce the new wood for the next winter pruning. 
 
 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 Ci, 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 
 being available {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 b, according to its vigor. 
 
 Summer 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. 
 
 Weakening Effect. — 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 Prin- 
 ciple No. 1, page 24. 
 
 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. 
 
— 31 — 
 
 The removal of all the leaves by defoliating insects at this time may 
 kill the vine. It 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 following year 
 because the weakness due to removal of leaves is more than counter- 
 balanced by the strengthening due to lack of crop. It is least harmful 
 late in the autumn after the canes have matured and the leaves com- 
 mence to turn yellow. 
 
 Concentrating Effect. — The removal of growing shoots or parts of 
 shoots has also an effect similar to that of winter pruning, viz, the con- 
 centration 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 almost as marked as that of winter pruning. In 
 early summer, with the vines in full growth, the weakening effect may 
 be sufficient to completely 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 weaken- 
 ing 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 on 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 
 
— 32 — 
 
 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 into 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 weaken- 
 ing to the vine and the concentrating effect is correspondingly less. It 
 is simpler than disbudding, as it necessitates going over the vineyard 
 only once. It is used principally during the second year for vines 
 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 
 can 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 become 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 growing vigorously, they appro- 
 priate 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 
 vigorous sucker. 
 
— 33 — 
 
 With grafted vines, the consequences are even more serious. The 
 suckers, coming from the stock, take the sap even more easily from the 
 top which is connected to the root by the union which impedes some- 
 what the passage of water and food materials. 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 dur- 
 ing 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 impor- 
 tant reason is that suckers which are removed late, and especially those 
 which are allowed to grow the whole summer, promote the formation 
 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 underground spur 
 or arm which will be a source of perennial trouble. 
 
 Water-sprouting. — 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 of the vine is not being used for the production of crop. 
 The cure for this is longer or a different style of winter pruning. The 
 production of sterile shoots on what ought to be fruit wood often indi- 
 cates 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 
 3— BUL241 
 
— 34 — 
 
 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 prun- 
 ing. Water-sprouts are sometimes troublesome by growing through the 
 bunches, making it impossible to gather the crop without injury. This 
 is particularly harmful with shipping grapes. Where much of tlr's 
 trouble exists, it indicates that the vine 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 pur- 
 pose they are better than fruitful shoots, being 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 inches to 18 inches long the shoot has time 
 to become tough enough 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." Pinching 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. Figure 9 shows a fruiting shoot at the proper stage 
 for the first pinching. 
 
 Topping. — This consists in removing one, two, or more feet of the end 
 of a growing shoot, usually in June and July or later. In some regions 
 topping is practiced regularly twice or even three times during the 
 season. In general, it is more used 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 laterals. 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 being broken off entirely by the wind. 
 The later the topping is done the more leaves are removed 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. 
 
— 35 — 
 
 In general, topping tends to increase the size of the grapes and to 
 decrease their quality. For table grapes on vigorous vines it is some- 
 times 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 defects 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 on 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, the weight 
 of the shoot tends to bend it over to a more or less horizontal or down- 
 ward direction. With some rapidly elongating varieties, the shoots 
 bend over and take a reclining position, resting for a considerable por- 
 tion of their length on the soil. With nearly all varieties they will 
 finally bend outwards and downwards sufficiently to open up the center 
 of the vine to the sun. 
 
 In many cases, this opening up of the center is an advantage, promot- 
 ing the coloring of the grapes and 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. This is proved by the fact that some 
 bunches completely 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 
 result. Defective or diseased roots, wounds or fungus in stem 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, involving the removal of feed- 
 ing leaves, may weaken the vine so much as to increase the trouble. 
 
— 36 — 
 
 A B 
 
 Fig 13. — Bunch of green grapes before (A) and after (B) thinning. 
 
— 37 — 
 
 Defoliating. — The development of the color of the grapes is influenced 
 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 commenced 
 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 to evaporate the moisture from 
 their surfaces quickly. 
 
 * ' Sheeping ' ' the vineyard or allowing sheep to eat the leaves immedi- 
 ately or soon after gathering the crop is undoubtedly a bad practice. 
 It removes the leaves before they have fulfilled their important 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 success by many 
 growers of Tokay, Black Morocco, Luglienga and other grapes, where 
 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 size. 
 
 No bunches are removed, but 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 branchlets should be removed principally from the part of the 
 bunch which 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 looks immediately after thinning, it will round out and be- 
 come regular before ripening. 
 
— 38 — 
 
 A long, narrow-bladed knife or a pair of grape- trimming scissors can 
 be used conveniently for this work. 
 
 Ringing. — This consists in the removal of a ring of bark from a 
 growing shoot or from a cane of the previous year. The ring removed 
 
 Fig. 14. — Black Morocco improved by thinning. 
 
 varies in width from one fourth to one third of an inch. If it is too 
 narrow, the wound heals too quickly and the full effect of the operation 
 is not obtained; if too wide, the shoot may die before the ripening of 
 the fruit. The ring is removed from a part of the shoot or cane just 
 below the fruit. This prevents the passage of the food material to the 
 
— 39 — 
 
 lower parts of the vine and causes its accumulation in the parts above 
 the incision and consequently in the fruit. 
 
 The result on the vines is weakening as in all kinds of summer prun- 
 ing. It can be used therefore only on vigorous vines, and usually only 
 on those parts which are to be removed at the following winter pruning. 
 
 Shoots may be ringed as soon as they commence to become woody at 
 the base, that is, a little before blossoming and until the time when they 
 commence to turn yellow or mature. The canes or spurs of the previous 
 winter pruning may be "ringed" from three weeks before blossoming 
 to a month before the ripening of the fruit. 
 
 Early ringing tends to cause the blossoms to set better and to combat 
 "coulure." It causes the fruit to ripen two or three weeks earlier and 
 often to increase the size of both berries and bunches. 
 
 Its weakening effects are greatest in hot climates and it is not used in 
 California. In Australia it is used regularly with the Black Corinth, 
 the vine which produces the small seedless grapes from which the cur- 
 rants of commerce are made. This vine is of such extraordinary vigor 
 that ringing may be practiced every year without injury. It is even 
 possible to ring the main trunk of the vine with good results. 
 
 The ringing may be done with an ordinary budding knife, but can 
 be done quickly and well only with one of the special instruments made 
 for the purpose. 
 
 Removal of Surface Boots. — 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, how- 
 ever, 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 irri- 
 gation 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 three or four inches of the surface. This can be done at 
 the same time that the vines are hoed and suckered. When grafted 
 vines are planted, the union is placed above 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 unusually unfavorable conditions 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 
 
— 40 — 
 
 are pruning wounds. Wounds are not only harmful in themselves by- 
 destroying wood, bark and other conducting tissues, but they allow the 
 
 ■■Mfea, — . jMllt. U- /"»• '.^s-bv. 
 
 
 
 \ dfefcgtfy^. • 
 
 : ■ ; ; " \. ■ - ■- ''•> - : ^ y i 
 
 .'• 
 
 1' **7*gl*i 
 
 
 
 '■ ' ^'- '^ '"■ . : : 
 
 I \i 
 
 lei" . 'V'^ ." . '*■ i 
 ' "? / * •* £jfH 
 
 
 Fig. 15. 
 
 -Spore bearing bodies of an "oyster-shell fungus" showing fungous 
 decay of the trunk due to large pruning wounds. 
 
 entrance of boring insects and wood destroying fungi whose effects are 
 even more destructive. 
 
— 41 — 
 
 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. 
 
 Useless shoots and canes should be removed while they are small and 
 young, 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 
 
 Fig. 16. 
 
 -Proper position of pruning shears with relation to the vine when mak- 
 ing a cut. 
 
 the inside by the production of gummy matters or thyloses which fill 
 up the cells and tissue and so prevent loss of sap. It does not cover 
 the wounds with healing tissue from the outside with the facility of 
 many fruit trees. Wounds much over an inch in diameter seldom heal 
 over completely. 
 
 By careful and skillful use of the pruning tools the harm of necessary 
 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 
 
— 42 
 
 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 
 entirely the blade of the shear should be placed against the vine, and 
 should cut upwards as shown in Fig. 16. 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 consider- 
 ably 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. 17. This leaves the 
 woody diaphragm intact and protects the spur from 
 injury. If the spur is cut at C x 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 and if 
 by mistake the cut is made just below the dia- 
 phragm the breeding place for molds has its maxi- 
 mum 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. 
 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 furnished 
 for the fruit canes. 
 
 Fig. 17. — Methods of 
 cutting the end of a 
 spur. 
 
— 43 — 
 
 The supports needed then are of two kinds: (1) Temporary supports 
 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 the 
 best, as sawn stakes may be cut diagonally across the grain and many 
 may break in driving. 
 
 Pine, spruce, poplar, willow or any available 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 copper 
 sulfate. Saplings and small branches can sometimes be used con- 
 veniently. 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. 
 
 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 wind-break. These are somewhat 
 slender for the purpose and require much readjusting, but will serve 
 when better is 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 which is tied to it, and 
 sufficient above the surface to extend for two inches above the height 
 at which 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 Carignan or Tokay, especially when growing in rich soil, a stake two 
 inches square and thirty-six to forty-two inches long is necessary. This 
 will permit the heading of the vine at eighteen to twenty- four inches. 
 
— 44 — 
 
 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. 
 
 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 convenient for this purpose as it serves also 
 for tying up the yearly replacing shoots. This stake, however, is 
 expensive and 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. 
 
 Fig. 18. — Pruning tools: (a) one-hand shears; (b) two-hand shears; (c) curved' 
 
 saw. 
 
 A temporary stake is used with each vine until it has developed a self- 
 supporting trunk. The wire 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 facilitates 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 
 are a little better as No. 12 will frequently break. 
 
 M 
 
- 45 - 
 
 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, how- 
 ever, is not quite strong enough for the main body of the vine, especially 
 in windy locations, unless doubled, though it is excellent for tying fruit 
 canes to stake or trellis. Old ropes, such as discarded ship cables, can 
 sometimes be obtained cheaply, and, if cut into suitable 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. 
 
 In the hands of very careful workmen, nothing is better than wire 
 
 Fig. 19. — Burning the brush in the vineyard after pruning. 
 
 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 a little 
 unnecessarily heavy. No. 16 galvanized fencing wire is 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. 
 
 Pruning Tools. — The best tool for pruning vines is a pair of shears 
 of the Swiss form (see Fig. 18). 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. 
 
— 46 — 
 
 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 Pruning s. — 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. 
 
 Fig. 20. — Vineyard brush burner. 
 
 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 they are sufficiently dry. 
 The heat from these fires is so great that it sometimes injures neighbor- 
 ing 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. 20. 
 
 This consists of an iron truck with a perforated bottom. A fire is 
 started in the truck which is then drawn slowly down a free row by a 
 quiet horse trained to the work. Two men collect the "brush" in the 
 adjoining rows and throw it into the moving truck where it burns 
 without danger of injuring the vines, and at a lower temperature than 
 
— 47 — 
 
 in the large piles. The ashes are distributed equally over the vineyard. 
 The method is difficult to adapt to trellised vineyards 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. In some countries the vine 
 primings 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 utilization in any of these ways. 
 
 Principle of Economy. — The skillful pruner directs as much as pos- 
 sible of the energy and growth of the plant into the permanent frame- 
 work 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, which is 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 
 makes use of 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, with- 
 out running the risk on the one hand of weakening the vine with an 
 over-supply of poor fruit, or, on the other, 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. 
 
48 
 
 TABLE OF CONTENTS. 
 
 PART I. 
 
 A. Introduction. 
 
 Page. 
 
 Literature: Need of the Bulletin 3 
 
 Definition: Objects; Scope 3 
 
 Some Results of Defective Pruning 4 
 
 B. Habit and Characteristics of the Vine. 
 
 Vitis Vinifera : Structure of a Cultivated Vine 7 
 
 Pruning and Descriptive Terms 9 
 
 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 22 
 
 Winter Pruning . 23 
 
 Season ; Amount ; Young and Old Vines ; Units of Pruning. 
 Summer Pruning 30 
 
 Weakening effect ; Concentrating effect ; Uses ; Disbudding ; Thinning of 
 
 Shoots ; Topping Young Vines ; Suckering ; Water-sprouting ; Pinching ; 
 
 Topping ; Defoliating ; Thinning the Fruit ; Ringing ; Cutting Surface 
 
 Roots. 
 
 Restriction and Treatment of Wounds 39 
 
 Supports: Staking; Trellising 42 
 
 Pruning Tools: Disposal of Prunings 45 
 
 Principle of Economy 47 
 
 ILLUSTRATIONS. 
 
 Cover Cut, Wild Vine of California (Vitis Calif ornica) . 
 
 Fig. 1. Trunks of V. Californica. 
 
 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. 11. Unit of short pruning. 
 
 Fig. 12. Unit of long pruning. 
 
 Fig. 13. Tokay bunch before and after thinning. 
 
 Fig. 14. Black Morocco bunch improved by thinning. 
 
 Fig. 15. Fungous decay due to large pruning wounds. 
 
 Fig. 16. Position of pruning shears. 
 
 Fig. 17. Method of cutting the end of a spur. 
 
 Fig. 18. Pruning tools. 
 
 Fig. 19. Burning the "brush" after pruning. 
 
 Fig. 20. Brush burner.