PRUNING 
 
 O RN AM ENTAL 
 
 Trees, Shrubs, and Vines 
 
 W. H. CHANDLER 
 
 RALPH D. CORNELL 
 
 
This rusty fig tree was trained after 
 the leader had been nearly shaded 
 out by lower, temporary branches. 
 Severe cutting back of the upper and 
 inner parts of these branches per- 
 mitted the leader to grow to this good 
 form. See page 14 for details. 
 
 The Authors: 
 
 William H. Chandler is Professor of Horticulture and Horticulturist in the Experiment 
 
 Station (Emeritus), Los Angeles. 
 Ralph D. Cornell is a landscape architect, Los Angeles. 
 
w 
 
 r E PRUNE AN ORNAMENTAL PLANT TO 
 
 adjust it to the unnatural conditions in which it may be grown. Some plants 
 are readily adaptable to these unnatural conditions, and do not need much 
 pruning except for the occasional removal of dead wood. Many trees are as 
 healthy and beautiful without pruning as with it, or may even do better when 
 growing naturally. But when they are grown close to buildings they must be 
 pruned to control the height of branches in relation to the building. 
 
 Among shrubs and vines there are certain kinds that must be pruned 
 heavily to keep them within bounds. Sometimes it is necessary to cut back 
 their upper branches in order to keep the lower ones in healthy condition, if 
 low branches are desirable in the situation where they are grown. 
 
 The wise pruner always tries to accomplish his purpose without butcher- 
 ing his plants, without making them look unnatural. He also tries to prune 
 his plants without risking the excessive loss of flowers that may result from 
 improper technique. He knows, too, that he may have to prune plants of the 
 same variety differently under different situations or different environments. 
 
 To try to give detailed pruning directions for all varieties of ornamentals, 
 in all situations, would make a bulky and not very helpful book. The best 
 help a gardener can get is knowledge of the way pruning affects the most 
 important processes in growth and flowering of his plants. If he has this 
 general knowledge, and also knows the special ways that pruning affects 
 a number of different kinds of plants, he can predict the effect it will have on 
 other kinds, or in other environments, without making many mistakes. 
 
 This circular presents a general survey of pruning fundamentals, with 
 many examples. We begin with a discussion of the plant processes that are 
 vital to understand how to prune and when to prune. We then discuss the 
 basic pruning methods. Following this we consider some of the main prac- 
 tical applications of pruning skill: training young trees; pruning to control 
 size; pruning columnar trees; pruning shrubs; and pruning vines. 
 
 Many of the varieties given as pruning examples in this circular are 
 especially well known in southern California. Others are common to all 
 California. In all cases the principles involved are applicable to pruning 
 anywhere in the state. An index of varieties discussed in this circular will 
 be found on page 43. 
 
 Table of Contents is on outside back cover. 
 
PRUNING AND PLANT 
 PROCESSES 
 
 Pruning reduces daily water losses of the plant by 
 reducing leaf surface. Thus it diverts more sugar — 
 the food produced by plants in sunlight — from root 
 production to shoot production, and increases suc- 
 culence of growth. 
 
 HOW PLANTS GET 
 FOOD FOR GROWTH 
 
 By food we mean the sugar that is pro- 
 duced in the plants in light by combining 
 water with the carbon dioxide that enters 
 the leaves from the air; starch that is 
 derived from sugar; other substances 
 such as organic acids produced from 
 sugars; and complicated compounds of 
 these with substances from the soil, espe- 
 cially nitrogen. Substances other than 
 water that the plant needs and obtains 
 from the soil are usually called nutrients 
 and rarely compose as much as 3 per cent 
 of its weight. New growth of roots and 
 top is largely from the sugar produced 
 in the leaves, and is usually greater in 
 full sunlight. A leaf in full sun does not 
 produce more sugar than one in slight 
 shade, but many leaves in the head of a 
 tree or shrub are in too much shade from 
 other leaves to produce the greatest pos- 
 sible amount of sugar. If most of the plant 
 is in some shade, as of a building or other 
 plants, more of its leaves will be shaded 
 too much for best food production, and 
 the leaves in most shade will die. Leaves 
 of some plants, however, have greater 
 ability than others to survive and to pro- 
 duce well in shade. 
 
 Openings in the leaves by which carbon 
 dioxide enters them also permit rather 
 great escape of water from them. Usually 
 in the sunniest part of the day, water is 
 lost from the leaves a little faster than 
 it is absorbed by the roots, even when 
 the soil is well supplied with water. If 
 the air is dry and the sunlight intense the 
 daily water deficits in the tree cells may 
 
 become large, especially if a considerable 
 part of the root system is in nearly dry 
 soil. 
 
 If the daily water deficits are slight and 
 the supply of nutrients from the soil ade- 
 quate, sugar produced in the leaves may 
 be used largely for growth of leafy shoots. 
 This, however, will increase the leaf sur- 
 face faster than the absorbing root system 
 increases. Daily water deficits will be- 
 come larger and check shoot growth. 
 Sugar that is not used by the reduced 
 shoot growth will move to the roots and 
 increase their growth and water absorp- 
 tion. In other words, when the soil is 
 continuously supplied with water and nu- 
 trients, the daily water deficit tends to 
 regulate (and to be regulated in consider- 
 able part by) the comparative growth of 
 leaves and of new roots. 
 
 Pruning, when it increases succulence 
 of growth, does so because the leaf sur- 
 face is reduced in proportion to the water- 
 absorbing ability of the roots: leafy 
 shoots are cut off, or buds that would 
 grow into leafy shoots, while, tempo- 
 rarily, the roots are not reduced. The 
 daily water deficits will therefore be re- 
 duced, because fewer leaves are losing 
 water. Less sugar will be produced for 
 the same reason. With their better water 
 supply, the shoots will grow rapidly and 
 use a larger percentage of the sugar sup- 
 ply, and root growth will be decreased. 
 With decreasing root growth and increas- 
 ing leaf surface, the daily water deficits 
 will increase and eventually cause reduc- 
 tion of shoot growth with a consequent 
 increase in the supply of food to the roots. 
 
 [4] 
 
A normal balance between absorption of 
 water by the roots and its loss by the 
 leaves will thus be reestablished. If the 
 pruning reduces the tendency of the plant 
 to flower well, this reduction may be due 
 to the greater succulence of shoot growth, 
 and such a tendency will be greater if 
 the plant is partially shaded and the ni- 
 trogen supply is abundant. Some kinds 
 of ornamental plants, however, will 
 flower in spite of the most succulent con- 
 ditions that severe pruning and shade and 
 nitrogen can produce. The way that prun- 
 ing is most apt to reduce flowering is by 
 the cutting off of branches containing 
 buds that normally would open into 
 flowers. 
 
 The smaller top of a severely pruned 
 tree has fewer shoots to use the nitrogen 
 that the roots can supply. Thus the re- 
 maining shoots have, temporarily, a bet- 
 ter nitrogen supply and may bear leaves 
 with the deep green characteristic of trees 
 with an abundance of nitrogen. A nitro- 
 gen deficiency reduces the rate of growth 
 and may increase the tendency to flower. 
 If the plant must be kept down to a space 
 much smaller than it would naturally oc- 
 cupy, it may be advisable to keep the 
 nitrogen supply low by withholding ni- 
 trogen fertilizers or even by keeping a 
 grass sod around the tree or shrub. This 
 will reduce the amount of pruning re- 
 quired. ■ 
 
 Such principles as these are compli- 
 cated in various ways, since different 
 kinds of plants respond differently. They 
 can be used wisely in decisions for prun- 
 ing only if supplemented by knowledge 
 concerning special growth and flowering 
 characteristics of different kinds of 
 woody plants. 
 
 PRUNING AND OLD BUDS 
 
 Many buds on a shoot remain dormant 
 when others are growing. Yet they re- 
 main alive and do not become covered 
 by the layers of new wood that form 
 around the shoot or branch. They elon- 
 gate enough each year to keep their tips 
 
 in the bark. If a branch is bent down- 
 ward, as in figure 1, so that some of these 
 old buds are near the top of the curve, 
 they may grow into long shoots, water- 
 sprouts, like those near the center in 
 the figure. Or if the branch is cut back 
 below all living shoots, new shoots may 
 grow from these old buds in the stub that 
 is left. Sometimes a tree or shrub is so 
 tall and straggling that all of its branches 
 may be cut back to stubs a few feet long 
 so that a new, more compact head will 
 grow from old buds in these stubs. 
 
 Trees and shrubs of a few kinds — such 
 as the Victoria tea tree, Leptospermum 
 laevigatum — seem to have no such old 
 buds with live tips in the bark. If the 
 branches of these are cut back below all 
 young shoots with leaves or buds, no new 
 shoots will grow and the part left will die ; 
 or if all branches are so cut back, the 
 plant will die. Plants in a few other spe- 
 cies (as some cypress trees) do not have 
 many old buds that will grow, and when 
 
 Fig. 1. Long shoots, watersprouts, in the cen- 
 ter, from old buds caused to grow by bending 
 the branches downward. 
 
 [5] 
 
stubs without live shoots are left, shoots 
 may or may not grow from them. When 
 all branches of a tree of such kinds are cut 
 back, shoots may grow from enough of 
 the stubs to keep the tree alive but not 
 from enough to give it a symmetrical 
 form. 
 
 PRUNING DECIDUOUS TREES, 
 SHRUBS, AND VINES 
 
 Summer rest period and winter chilling 
 requirements are chief considerations in 
 pruning woody deciduous plants. For best 
 growth, prune between leaf fall and first 
 spring growth. 
 
 At some time in summer, plants of most 
 woody deciduous species — such as the 
 apple and the peach — develop a condi- 
 tion known as the rest period. This pre- 
 vents buds from growing after shoot 
 elongation has ceased and a bud has 
 formed at the tip of each shoot. Thicken- 
 ing of trunk and branches by cambial 
 growth ceases soon after shoot elongation 
 ceases. However, roots do not seem to 
 have a rest period and the greatest root 
 growth of the year will be in late summer 
 and autumn, after food use in top growth 
 has declined greatly. Root growth, how- 
 ever, does not use nearly all the food from 
 the leaves, and much starch is stored in 
 all woody parts of the plant. In spring 
 this stored starch is changed back to 
 sugar gradually and used in growth. This 
 food and the surplus nutrients stored in 
 the tree are enough for rapid develop- 
 ment of new absorbing roots. 
 
 Winter and spring pruning. Prun- 
 ing deciduous trees, shrubs, or vines 
 while they have this rich store of food 
 and nutrients (any time between leaf fall 
 and the beginning of growth in spring) 
 reduces the amount of leaf surface to be 
 produced. With a smaller leaf surface, 
 less water will escape. Because of the rich 
 store of food in the roots from the pre- 
 ceding year, their production of new ab- 
 sorbing roots is not reduced soon. Daily 
 water deficits will tend to be smaller than 
 
 on unpruned trees and shoot growth to 
 be more rapid and succulent, and to con- 
 tinue later in summer. The more severe 
 the pruning before growth starts, the 
 more rapid the new shoot growth will be, 
 the later in summer it will continue, the 
 longer and more upright the shoots will 
 become, and the larger and darker green 
 their leaves will be. This invigorating ef- 
 fect is not all on branches close to where 
 the cut is made: when a large branch is 
 cut off or cut back severely in the dormant 
 season, spring shoot growth tends to be 
 more vigorous throughout the head of 
 the tree. But cutting a branch back to a 
 lateral branch that is weak, owing to 
 shade or other unfavorable position, will 
 usually invigorate the weak lateral more 
 than other branches are invigorated, by 
 giving it a more favorable position. 
 
 After succulent spring shoot and root 
 growth has nearly exhausted the supply 
 of reserve starch, growth of new rootlets 
 will be slower, while the leaf surface and 
 water loss are increasing. Daily water 
 deficits will thus increase and eventually 
 stop shoot growth, but later than on an 
 unpruned tree. Yet the total leaf surface 
 will be somewhat smaller than on an un- 
 pruned tree. Abundant storage of food 
 begins a little later and is a little slower, 
 owing to the reduced leaf surface. Late 
 summer and autumn root growth also is 
 slower. Unless the pruning has been ex- 
 ceptionally severe, the balance between 
 absorbing ability of the roots and water 
 losses at the leaf surface will be about 
 the same on a pruned as on an unpruned 
 tree by the end of the season, with the 
 pruned tree reduced in size. The invigo- 
 rating effect that pruning has on shoot 
 growth tends to last only part of one sum- 
 mer. And in spite of the larger leaves and 
 longer shoots, the number of leafy shoots 
 and the total leaf area have been reduced. 
 Total growth of wood above and below 
 ground is reduced owing to the smaller 
 leaf surface. 
 
 Summer pruning. If the deciduous 
 tree, shrub, or vine had been pruned as 
 
 [6] 
 
severely in midsummer soon after the 
 buds had gone into the rest period, the 
 reduced leaf surface during the remain- 
 der of the summer would have reduced 
 root growth to such an extent that shoots 
 would probably have grown no faster in 
 the following spring, and leaves have be- 
 come no larger, than if it had remained 
 unpruned. The reduction in size of the 
 tree, shrub, or vine would have been 
 greater than if the pruning had been done 
 at any other time. If the pruning had 
 been done earlier in summer before the 
 rest period had begun, some new shoot 
 growth would have been made so that late 
 summer leaf surface and root growth 
 would have been a little greater than if 
 pruning had been done just after the buds 
 had all gone into the rest period. If the 
 pruning had been done some weeks or 
 months after the buds had gone into the 
 rest period, the reduced leaf surface and 
 slower root growth would have occurred 
 during a shorter period and growth 
 would have been a little more vigorous in 
 the following spring, but not as vigorous 
 as if the pruning had been in winter or 
 spring. In other words, after a year of 
 growth following equally severe pruning 
 of deciduous woody plants, the least re- 
 duction in size is by pruning done in late 
 autumn, winter, or early spring, and the 
 greatest by that done in midsummer. 
 
 Pruning and chilling require- 
 ments. In climates like parts of Califor- 
 nia, where there is not enough chilling 
 weather in winter to break the rest period 
 of some deciduous plants completely, 
 opening of the buds of kinds with mod- 
 erate to long chilling requirements is 
 delayed, sometimes greatly. And bud 
 opening on a plant may be uneven, with 
 some buds opening long before others, so 
 that the tree or shrub looks straggling 
 for a considerable time in spring. Flowers 
 may die in the bud or during the process 
 of opening. To some degree at least, the 
 later a deciduous shoot grows in summer 
 or autumn, the more chilling its buds re- 
 quire before they will open normally in 
 
 spring. After a warm winter, long water 
 sprouts that grew late in the summer be- 
 fore may be considerably later in opening 
 their buds than are shoots on the same 
 tree that ceased growth much earlier in 
 that summer. Pruning deciduous trees, 
 shrubs, or vines severely in winter, 
 spring, or early summer causes the shoots 
 to grow much later and to need more 
 chilling in the following winter to release 
 their buds from the rest period. After 
 warm winters, deciduous woody plants 
 that were so pruned a year before and 
 made such late growth in the summer will 
 be slower to open their buds. Moderate 
 pruning such as usually would be given, 
 however, has very little effect on the nor- 
 mal chilling requirements of buds on the 
 shoots that grow after the pruning. 
 
 Pruning near midsummer increases the 
 chilling requirement of buds left on the 
 tree at pruning time more than spring 
 pruning increases the chilling require- 
 ments of buds on shoots that grow in 
 summer following the pruning. Such mid- 
 summer pruning, though followed by no 
 new growth in the top, seems to delay 
 maturing of the wood and in some way to 
 impede the process by which winter chill- 
 ing releases the buds for growth. 
 
 PRUNING BROADLEAVED 
 EVERGREEN TREES, SHRUBS, 
 AND VINES 
 
 Evergreens have several growth flushes 
 and no rest period. They may be pruned 
 into midsummer, but never show as greal 
 shoot invigoration as deciduous trees 
 pruned in spring. 
 
 Evergreen pruning has had much less 
 study than deciduous pruning, but what 
 we know of the latter can help towards 
 understanding evergreen responses. 
 
 Broadleaved evergreen trees such as the 
 orange and the avocado and many orna- 
 mental trees, shrubs, and vines, do not 
 have a rest period that must be broken by 
 chilling before their buds can grow; and 
 so they are not apt to have a long period 
 
 7] 
 
in late summer when the top is using no 
 food for shoot growth or cambial growth 
 and when the roots are getting enough 
 food for exceptionally abundant growth. 
 Plants of most such species do not store 
 as much starch in late summer as decid- 
 uous trees do. Most abundant leafy shoot 
 growth on plants of these evergreen kinds 
 may not always be made in spring and 
 early summer, as it is on deciduous plants. 
 Pruning done at any time does not in- 
 crease shoot elongation as much as 
 equally severe pruning in winter or spring 
 increases spring shoot elongation of de- 
 ciduous plants. Pruning at any time, 
 therefore, dwarfs evergreen trees more 
 than equally severe pruning in winter or 
 spring dwarfs deciduous trees. 
 
 Plants of most broadleaved evergreen 
 species are apt to produce one or more 
 growth flushes after midsummer, and are 
 not apt to stand long without leafy shoot 
 growth after a midsummer pruning, so 
 
 that pruning in midsummer should not 
 dwarf a broadleaved evergreen tree as 
 much as it dwarfs deciduous trees. The 
 only time an evergreen tree is apt to be 
 in as long a period without shoot growth, 
 as a deciduous tree in leaf may be after 
 midsummer, is when the weather is too 
 cool for growth of the evergreen species 
 concerned but not too cool for sugar pro- 
 duction. And if pruning at any time 
 dwarfs a broadleaved evergreen as much 
 as equally severe midsummer pruning 
 dwarfs a deciduous tree, that time is prob- 
 ably in late autumn. Then the tree may 
 stand with its reduced leaf surface and 
 with no new leafy shoot growth until 
 spring, or until summer if springs are too 
 cool for growth of the species concerned. 
 However, pruning at any season will 
 dwarf most evergreen ornamental species 
 grown in California less than equally 
 severe pruning in midsummer dwarfs 
 deciduous plants. 
 
 Fig. 2. Eleven-year-old Bishop pine (Pinus 
 muricata) less than 8 feet tall, kept small by 
 pruning severely each spring, cutting each main 
 branch back to its lowest healthy lateral branch. 
 
 PRUNING CONIFERS 
 
 Many conifers have only a spring 
 growth flush: prune them just ahead of it. 
 
 Some of the species of arborvitae 
 {Thuja), cedar {Cedrus) , cypress (Cu- 
 pressus) , false cypress (Chamaecyparis) , 
 junipers (Juniperus) , pines {Pinus), 
 yews {Taxus), and other conifers, may 
 have only a spring or early summer 
 growth flush, like most deciduous species. 
 Pruning just after this flush is completed 
 will leave such trees with reduced leaf 
 surface during late summer, autumn, and 
 winter, and should therefore dwarf them 
 as much as pruning at that time would 
 dwarf deciduous trees. Since the needles 
 removed in pruning would be producing 
 some sugar during mild days in winters, 
 the dwarfing might be even greater. The 
 least dwarfing effect should follow 
 pruning in spring just before a growth 
 flush starts. Trees of some of these genera, 
 such as Cedrus, and of some species of 
 the other genera will grow whenever it is 
 warm enough, and pruning may well be 
 
 [81 
 
done at any time, possibly excepting late 
 autumn or early winter, if many leafy 
 shoots are to be removed 
 
 There is an opinion among some gar- 
 deners that pruning conifers may kill 
 them. This may be true in some situations 
 for some kinds, but some pine species 
 which are normally very large will sur- 
 vive pruning enough to keep them in 
 rather low hedges. Figure 2 shows a 
 Bishop pine 11 years old, kept down by 
 pruning to perhaps 10 per cent of the size 
 it would have if left unpruned, and yet it 
 is very healthy. Some of the other conifers 
 can be even more effectively trained to 
 any small size wanted. 
 
 Trees in many conifer species do not 
 have living buds in old wood. In such, if 
 a branch is cut back to old wood with no 
 living shoots, no new shoots will grow 
 from the part left and it will die. Except 
 in species known to have live bud tips in 
 old wood, a branch should be either cut 
 off close to the part to which it is at- 
 tached, or cut back only to living leafy 
 branchlets that can grow and be invigor- 
 ated by the pruning. Leafy pine stubs 
 from which the terminal bud has been 
 removed cannot always be depended on 
 to grow new shoots from lateral buds in 
 the axils of needles. The best plan is to 
 cut back to branches that have healthy 
 terminal buds. (See figure 4 ahead.) 
 
 PRUNING AND COLD RESISTANCE 
 
 Summer pruning can lower resistance 
 in cold-resistant plants. 
 
 The development of maximum cold re- 
 sistance, in those kinds of plants that do 
 develop considerable resistance, requires 
 the greatest possible late summer and 
 autumn leaf surface in proportion to the 
 size of the tree or shrub. Pruning in sum- 
 mer that is not followed by new leafy 
 shoot growth may considerably reduce 
 the resistance that plants of such kinds 
 will develop. 
 
 Even in rather tender evergreen kinds, 
 a large healthy leaf surface in autumn 
 
 and winter helps hold the buds inactive 
 and supplies something necessary , for 
 development of as much cold resistance 
 as possible. In such tender kinds, how- 
 ever, the greatest differences in frost dam- 
 age on a cold night are apt to depend on 
 temperature differences at different situ- 
 ations even within a small area. 
 
 CHOOSING TIMES TO PRUNE 
 
 Light pruning is safe anytime. In severe 
 pruning, you must consider (1) time of 
 shoot growth, (2) effect on flowering, (3) 
 effect on fruiting. 
 
 We have seen that the best time to prune 
 deciduous trees and conifers, to cause 
 growth of long shoots with large leaves, 
 is in winter or in early spring before or 
 during the opening of buds. This may 
 also be true for many broadleaf ever- 
 greens. Plants of some evergreen species, 
 such as the hibiscus, however, do not 
 make much shoot growth until warm 
 early summer weather begins. If these 
 are pruned in winter or very early spring, 
 the reduction in leaf surface during this 
 long cool period may so reduce root 
 growth that considerably less increase in 
 length of shoots or size of leaves will re- 
 sult. For this reason, a better time to 
 prune them — if they must be pruned 
 severely — may be late in April or even 
 early May (in California coastal dis- 
 tricts) . 
 
 If only a little pruning is necessary, it 
 may be done at any time on deciduous or 
 evergreen trees, shrubs, or vines. Cutting 
 off a single large branch or a considerable 
 number of very small ones may be done 
 at any time without injury. 
 
 More important to consider are the 
 effects pruning may have on flowering or 
 fruiting. Severe pruning of some kinds 
 reduces the tendency to flower. Other 
 kinds, such as the crape-myrtle (Lager- 
 stroemia) , of some varieties at least, can 
 be cut off at the ground during the dor- 
 mant season, and the sprouts that grow up 
 in spring and summer following may 
 
 [9 
 
flower heavily. Such responses and other 
 aspects of the flowering habit of the kind 
 must be considered in choosing a time to 
 prune. 
 
 If the plant is one that bears spring 
 flowers from buds in which flower initials 
 began to form in the preceding summer, 
 and that does not bear fruit that is beauti- 
 ful or useful, the best time to prune will 
 usually be just after the flowers fall. If 
 it bears bruit that is beautiful, severe 
 pruning at this time may not be advisable : 
 it may cause excessive growth of new 
 shoots that hide the fruit. If the fruiting 
 plant is in a good situation for flowering, 
 the best time to prune may be just after 
 the fruit falls. Trees or shrubs growing 
 in partial shade, however, cannot always 
 be depended on to flower heavily on all 
 branchlets. Some kinds of cotoneasters, 
 for example, when growing in full sun- 
 light will flower on all shoots, but in par- 
 tial shade some shoots or branches may 
 not bear flowers. The best time to prune 
 such shaded plants when ornamental fruit 
 is wanted is during the bloom or soon 
 afterward, when the flower or fruit clus- 
 
 ters can be seen and left ; branches cut off 
 can be mainly those that will bear little 
 or no fruit. 
 
 If the plant is one that bears flowers 
 through the summer on new shoots, the 
 best time to prune will usually be in late 
 winter or early spring, just before a 
 growth flush starts. Such summer- 
 blooming plants of most species will tend 
 to bloom well even after very severe prun- 
 ing. However, some shrubs grow so vig- 
 orously that if they must be kept down to 
 a limited space, additional pruning in 
 summer may be necessary even after 
 severe spring pruning. Even with the most 
 cautious selection of branchlets for re- 
 moval this may cause a period in summer 
 when there is little or no bloom, but it 
 may also cause a stronger bloom with 
 fresher, brighter foliage later in the sum- 
 mer or autumn. If such a plant fails to 
 bloom in late summer or autumn after a 
 rather severe summer pruning and does 
 not make much growth, delaying the 
 pruning in the following spring until 
 after the first flush of bloom may be ad- 
 visable. 
 
 PRUNING METHODS: CUTTING 
 TO STUBS OR TO LATERALS 
 
 Cutting to stubs makes a compact head. Cutting to 
 laterals preserves natural form. 
 
 Two methods of shortening branches 
 are used. One is cutting back each shoot 
 or twig part way, leaving usually several 
 buds at its base, as figure 3 shows at the 
 left. At the right such a shoot stub is 
 shown in summer after the pruning. Sev- 
 eral new shoots have grown close to each 
 other. The head of the shrub is much more 
 compact than if these shoots had not been 
 cut back. On straggling trees this may be 
 desirable, but on many it makes the head 
 too compact and formless, increases the 
 number of branchlets killed by shade, and 
 makes the branch leaders less attractive in 
 appearance. A tree or shrub so pruned 
 
 annually will have branches on many 
 short stubs left from branch leaders, in- 
 stead of a few sturdy main branches with 
 laterals arising from them at well spaced 
 positions. Trees or shrubs pruned by this 
 method alone must gain some in height 
 and spread each year, whether there is 
 room for them or not. Often this cutting 
 back is done with large clippers such as 
 are used in trimming hedges, and the re- 
 sults are very objectionable. The plant 
 loses resemblance to the natural form of 
 any kind of tree or shrub and becomes a 
 compact cylinder or globe of leafy shoots 
 surrounding an impervious mass of dead 
 
 [10] 
 
Fig. 3 (left). The three branches at right start close together from a shoot that has been cut back 
 as at A on the shoot at the left. If each of these three branches should be cut back as at A, a thick 
 mass of such branches would grow. If all shoots on the tree or shrub should be so pruned, its outer 
 surface would become a compact mass, showing none of the natural beauty of the plant. Fig. 4 
 (right). A branch with its laterals as at A, B, and C. A bar near A indicates where the central stem 
 may be cut back to a lateral in moderately severe pruning. In more severe pruning the branch may 
 be cut to the lateral at B or C or even lower, if there is an upward-growing lateral lower on the 
 main branch. 
 
 stubs, old leaves, spider webs, and other 
 material. Such masses cannot be washed 
 out with the hose, owing to the thick cov- 
 ering of leafy shoots. The plants become 
 grotesquely rigid, without any natural 
 softness. 
 
 The other method of shortening 
 branches is cutting back to lateral 
 branches starting somewhere along the 
 leader, as figure 4 shows at A. This, of 
 course, is less work, for one cut removes 
 a number of shoots with the terminal part 
 of the branch. It will stimulate growth in 
 the lateral that is left to become the ter- 
 minal part of the branch that has been cut 
 back, but it does not increase the number 
 of terminal parts, as leaving shoot stubs 
 
 does. By this method the tree or shrub, 
 though reduced in size, can be left look- 
 ing as natural as an unpruned one, and 
 with the head open enough for the 
 branching system to show and to permit 
 dead material to be easily cleaned out 
 and light to show through the head. In 
 figure 4 part of a branch is shown with 
 its laterals as at A, B, and C. Cutting to 
 one of the laterals above A would be light 
 pruning. Cutting to lateral A would be 
 moderate pruning, to lateral C rather 
 severe pruning. If a tree or shrub must 
 be kept much smaller than it would nat- 
 urally become, branches may be cut even 
 farther back than to C, to laterals that 
 may be small and weak. These laterals will 
 
 pi] 
 
grow rapidly and soon develop good ap- 
 pearance. On some plants whole branches 
 like this can be cut out and smaller ones 
 left; there may be enough of these to give 
 the head a natural appearance even after 
 all its largest branches have been cut out. 
 
 To keep a tree leader or branch leader 
 nearly straight, the pruner may cut to a 
 lateral on one side of the leader, as at A, 
 in one year; to one on the opposite side, 
 as at B, in the succeeding year; and at C 
 in the third year. 
 
 TRAINING YOUNG TREES 
 
 To get the young tree to the size you want as fast 
 as possible, do the necessary training with a mini- 
 mum amount of pruning. 
 
 A tree left completely unpruned will 
 be larger than if it had been pruned at 
 any time by any method. In a wild situa- 
 tion, such an unpruned tree is apt to be 
 more beautiful than one pruned in any 
 way. On trees of many kinds, however, a 
 large part of the growth will be in the 
 lowest branches unless the lower part of 
 
 Fig. 5. Arizona ash, Fraxinus valutina. A 
 heavy top and slender trunk will make stak- 
 ing necessary for several years. No temporary 
 branches were left along the trunk to hasten 
 thickening and growth of roots and to retard 
 growth of the top until trunk and roots can 
 support it. 
 
 the tree is in dense shade. In a planting 
 for a home or a public building such 
 large, low branches will be in the way. 
 Besides preventing the growth of grass 
 under them, they may obstruct the view 
 of the building or of beautiful parts of 
 the landscape. Some training, therefore, 
 usually must be done. On most trees 
 around the home or along the street, the 
 lowest permanent branches are usually 
 wanted at a minimum of eight feet from 
 the ground so that people can walk under 
 them and grass will grow well, and, if 
 they are large, so that the homes will 
 show under them. 
 
 People are nearly always anxious to 
 have the young tree become large enough 
 to give the effect wanted from it as 
 quickly as possible. If the soil is well sup- 
 plied with air for the roots and with water 
 and nutrients, the most important means 
 of getting the young tree to this size as 
 fast as possible is to do the necessary 
 training with a minimum of pruning. 
 This makes a minimum reduction in leaf 
 surface. 
 
 DECIDUOUS TREES 
 
 On young deciduous trees of most 
 kinds, cutting away the branches each 
 year in winter while the leaves are off 
 will hasten the growth in height of the 
 trunk, and shorten the time until it is 
 tall enough for permanent branches to 
 be left. But the trunk will be more slender 
 than if branches had been left tempo- 
 rarily along it, and the root system a 
 
 r 12 
 
little smaller. The young tree with no 
 temporary branches left along the trunk 
 will require strong staking to keep it 
 straight against a fairly strong prevailing 
 wind. Figure 5 shows a young Arizona 
 ash tree trained by cutting off all branches 
 each winter until it was tall enough for 
 permanent branches. Even though a 
 strong stake extends well up among the 
 branches, the head has become consider- 
 ably heavier on the side away from the 
 wind. This is readily corrected by prun- 
 ing back the branches on that heavy side ; 
 but unless the staking is strong, some 
 trees so trained are broken in the wind. 
 Other ash trees in this planting were 
 trained by leaving temporary branches 
 beginning about ten inches from the 
 ground and spaced along and around the 
 trunk six to 12 inches apart. Each winter 
 the upward-growing parts of temporary 
 branches, the parts whose leaves would 
 injure new shoots from the trunk by 
 shade, were cut back to outspreading 
 laterals. These temporary branches were 
 left several years after permanent 
 branches began to grow, the largest being 
 cut out each year until all were removed. 
 Leaving these temporary branches along 
 the trunk made the trees about a year late 
 in becoming tall enough to start perma- 
 nent branches, and made growth of per- 
 manent branches a little slower but more 
 upright, with more resistance to prevail- 
 ing wind. The trunk diameters were 
 larger, especially toward their bases, and 
 the root systems were a little larger. When 
 the temporary branches were removed, 
 increased growth of permanent branches 
 in the summer following was enough to 
 make them as large as those on trees that 
 had no temporary branches left. Stakes 
 were not needed on these trees after the 
 first two or three years. Until a system 
 of permanent branches is established, 
 trees with temporary branches left are 
 more attractive in appearance than trees 
 without them. Along a street, however, 
 low, temporary branches may obscure 
 the view of drivers. 
 
 In some cities, deciduous street trees 
 are tall enough to start permanent 
 branches when they are planted and all 
 lower branches have been cut off. These, 
 of course, require especially strong stak- 
 ing. Some kinds, such as plane trees, do 
 not yield to the wind as much as ash 
 trees. The advantage of leaving tempo- 
 rary branches is not nearly so great for 
 most kinds of deciduous trees as it is for 
 evergreen trees. For street planting, ex- 
 cepting with a few kinds such as liquid- 
 ambar on which low temporary branches 
 require little attention until they are re- 
 moved, the advisable practice may be to 
 plant trees that are tall enough for the 
 growth of permanent branches and that 
 have all lower branches cut off. This 
 would require the use of strong stakes 
 that extend 3 or 4 feet above the lowest 
 permanent branch. 
 
 BROADLEAVED EVERGREENS 
 
 Planting these bare-root, as deciduous 
 trees are planted, can result in heavy 
 losses in the climate of California. If they 
 are tall enough when planted for perma- 
 nent branches to be left eight feet or more 
 from the ground, they will have to be 
 planted with some of their roots undis- 
 turbed in large masses of earth held from 
 breaking by boxing, an expensive prac- 
 tice. Evergreen trees are usually three 
 to five feet tall when planted. If the low- 
 est branches must be eight feet above 
 ground, trees must be trained during sev- 
 eral years after planting to maintain a 
 central stem on which the permanent 
 branches will eventually grow. 
 
 Tree trunks of some kinds of broad- 
 leaved evergreens elongate more each 
 year if all branches are cut off annually, 
 except a very few leafy ones around the 
 top. But such pruning does not increase 
 the rate of elongation of trunks of these 
 kinds nearly as much as it increases that 
 of deciduous trees, and in some evergreen 
 kinds such as camphor does not increase 
 it at all. Furthermore, such cutting away 
 of leafy branches reduces the rate of 
 
 [13] 
 
Fig. 6. Rusty fig, Ficus rubiginosa. Temporary 
 branches left unpruned have weakened the 
 leader branch by shade so that it is smaller 
 than the temporary branches that, being on the 
 outside, have the better light. 
 
 thickening and stiffening of the trunk of 
 evergreens much more than of decidu- 
 ous trees. Leaving temporary branches 
 spaced along trunks of young broad- 
 leaved evergreen trees is, for these rea- 
 sons and for more attractive appearance 
 of the young trees, nearly always advis- 
 able, if careful attention will be given to 
 their training. 
 
 Lower branches that grow upward as 
 well as outward tend to shade off parts 
 of branches starting higher on the trunk 
 and therefore to weaken the trunk. Be- 
 cause it has its leafy branchlets on the 
 outside of the tree head in good light, 
 an upward-growing lower branch left 
 unpruned will eventually become larger 
 than a trunk surrounded by such lower 
 branches. Such a trunk, if it does not 
 die out completely, at least becomes 
 slender and weak. Obviously the most 
 important way to prevent such weaken- 
 ing of the trunk is to cut off the upward- 
 
 growing parts of lower temporary 
 branches, cutting back to outward-grow- 
 ing laterals on them. Such outward- 
 growing laterals may become too long 
 and it will then be advisable to shorten 
 them back, to keep them out of the way. 
 Branches on trees of some kinds tend not 
 to grow upward but only outward. Such 
 trees may be more easily trained, but the 
 temporary branches will usually require 
 some shortening-in to keep them out of 
 the way, to keep their bases from becom- 
 ing so large that the wound left when 
 they are cut off will be too long in heal- 
 ing, and to hasten the elongation of the 
 trunk a little. In some kinds, such as the 
 magnolia, these temporary branches may 
 not need pruning as often as once a year 
 to keep them small enough. In most kinds 
 annual pruning is advisable, and in some 
 
 
 Fig. 8. Rusty fig (Ficus rubiginosa) consider- 
 ably younger than tree in fig 6. Left, before 
 pruning; right, after pruning at the top to keep 
 leaves on the leader from damage by shade of 
 other branches. By leaving temporary branches 
 
 14 
 
kinds, such as the carob, these lower 
 branches are apt to grow fast enough to 
 make pruning twice a year advisable. 
 
 Rusty Fig. Figure 6 shows a tree of 
 the rusty fig, Ficus rubiginosa, in which 
 each of a whorl of low, temporary 
 branches has become larger than the cen- 
 tral leader. All these large branches must 
 eventually be cut off. In order to impede 
 their growth and give better light to leaf 
 surface on the leader, the upper, inner 
 parts of each of these lower branches was 
 pruned severely. Such pruning caused 
 the leader to outgrow these lower, tempo- 
 rary branches greatly, as figure 7 shows. 
 Some temporary branches have been cut 
 off and others must be removed after the 
 trunk and brace roots have become 
 stronger. The picture on page 2 shows 
 this same tree after two more years of 
 
 from the beginning, growth was encouraged; by 
 cutting back the upright parts of these branches 
 to spreading laterals, growth of the leader was 
 made stronger than that of any other branch, 
 so that a leader was trained without staking. 
 
 Fig. 7. Rusty fig (Ficus rubiginosa) that was 
 originally like fig. 6. Upright parts of temporary 
 branches were later cut back to spreading lat- 
 erals so that leafy shoots higher on the leader 
 could receive good light. After four or five years 
 of such pruning, the leader is much larger than 
 the other branches. 
 
 training. Figure 8 is of another tree of 
 this species half as old, planted six 
 years later. By leaving lower temporary 
 branches that do not have much leverage 
 in the wind, it has been trained without 
 stakes. It is now tall enough for the new 
 branches at the top to be permanent ones. 
 The temporary branches will continue to 
 be kept from becoming too large by prun- 
 ing off their upper and outer parts; and 
 they will be cut off, a few each year, the 
 largest or most crowding first, as the 
 trunk and roots become large enough to 
 support the permanent branches against 
 the wind. The lower branches do not 
 merely increase the growth of trunk and 
 roots; they also reduce, temporarily, the 
 growth of permanent branches that are 
 farther from the ground, where they give 
 the wind a stronger leverage to blow the 
 tree over. Although these lower branches 
 
 [15] 
 
Fig. 9. Camphor trees, Cinnamomum camphora. Tree at left had all but a few leafy branches 
 cut off each year. Tree at right had most of these branches left but upright parts were cut back to 
 spreading laterals; its head is much the larger, but it could stand against the wind without a stake 
 at least two years sooner than the other tree. 
 
 Fig. 10. Young trees of California live oak, Quercus agrifolia. Tree at left had all but a few 
 branchlets at the top cut off each year. Temporary branches remained on tree at right but were 
 cut back to spreading laterals: lower branches become the largest part of the head of a live oak 
 otherwise. 
 
must eventually come off, leaving them 
 temporarily is not wasteful of the food 
 produced by the tree. They bear leaves 
 that supply enough food for their own 
 growth and for increased growth of roots 
 and trunk, and thus increase the tree's 
 food supply. 
 
 Camphor Tree. Figure 9 is of two 
 camphor trees, Cinnamomum camphora, 
 one with the lower branches cut off each 
 year while it was small, the other with 
 most of these branches left but with each 
 one cut back to outspreading laterals. 
 Cutting off lower branches of camphor 
 trees did not increase elongation of the 
 trunk, but in all cases seemed to reduce 
 it. And it reduced the rate of thickening 
 
 of the trunk greatly. Trees with these 
 lower branches left temporarily would 
 stand without stakes at least two years 
 sooner than the others. On camphor trees, 
 as on some others, the terminal shoot of 
 the central leader is apt to be weakened 
 by shade or some other influence from 
 surrounding shoots unless these are cut 
 back a little while they are young and 
 succulent, to give the leader shoot the 
 advantage. 
 
 California Live Oak. In figure 10 
 are two young California live oak trees, 
 Quercus agrifolia. Trees of this species 
 have a strong tendency for the lowest 
 branches to grow most rapidly into a 
 rather low spreading head, yet it is easily 
 
 Fig. 11. A carob tree (Ceratonia siliqua) tall enough for permanent branches, before and after 
 pruning temporary branches, which are left to strengthen the trunk and retard growth of branches 
 at the top so that they will remain upright on a trunk strong enough to support them. All tempo- 
 rary branches are cut back to where only a few leaves with buds in their axils are left to grow new 
 leafy shoots. This severe cutting keeps the temporary branches from becoming so large that the 
 wounds left will be slow to heal. Spring growth from the temporary branches soon filled the space 
 below the permanent branches and gave the tree a better appearance. 
 
 [17] 
 
Fig. 12. Two carob trees (Ceratonia siliqua) 
 with trunks made strong by leaving temporary 
 branches along them but shortening them in 
 twice a year. These seedling trees vary in 
 growth habits, and the method has not kept the 
 leader at right from growing too fast and being 
 bent out of line by the prevailing wind. By cut- 
 ting it back to an up-growing lateral, a straight 
 enough trunk will be maintained. 
 
 trained to a form with a central leader 
 extending high enough for the lowest 
 permanent branches to be eight to 12 feet 
 or more from the ground. All that is 
 needed is to cut the low, temporary 
 branches back a little each year to spread- 
 ing laterals. Like the camphor trees, the 
 trunks of these trees will be slow to gain 
 strength enough to stand without stakes, 
 if all branches except a few around the 
 top are cut off each year until the trees 
 are tall enough for permanent branches 
 to start. For this photograph the stake 
 was removed. 
 
 Carob. Figure 11 is of a carob tree, 
 Ceratonia siliqua, with the lower, tempo- 
 rary branches left but shortened twice a 
 
 year until it is six years old, and the trunk 
 has become strong enough to support a 
 top that will grow rapidly after these tem- 
 porary branches are removed. These will 
 be cut off gradually through a period of 
 several years, the largest first. Cutting off 
 all but a few branches at the top each 
 year from the time the tree is planted, 
 as at the left in figures 9 and 10, causes 
 more trouble on carob than on camphor 
 or live oak trees. The trunk gains 
 strength more slowly and the permanent 
 branches grow too rapidly and bend 
 downward from their weight. More up- 
 right permanent branches will be ob- 
 tained if their growth is retarded by 
 competition with temporary branches 
 along the trunk, and especially if, when 
 their direction of growth is being deter- 
 mined, temporary branches close under 
 them are crowding them upward. Unlike 
 camphor and live oak branches, carob 
 branch parts that droop grow about as 
 fast as upright parts. Pruning temporary 
 branches, therefore, cannot be merely a 
 cutting off of upward-growing parts. If 
 the soil is good, drooping and spreading 
 parts become too long and must be short- 
 ened-in, usually twice a year for best re- 
 sults. Like the camphor tree, the carob 
 tree on which temporary branches are 
 not left will tend to sprout badly in spring 
 around the base of the trunk, apparently 
 because of the small number of leafy 
 shoots left around the top after the prun- 
 ing. 
 
 Leaving temporary branches on young 
 carob trees will keep the leader upright 
 without the necessity of staking. The tree 
 in figure 11 had a one-inch stake only 
 while it was small, its first two or three 
 years. Sometimes, however, leaving these 
 branches does not keep the youngest part 
 of the leader upright. In such a case a 
 light stake may be used until the tree is 
 tall enough for the beginning of perma- 
 nent branches, or a bent leader can be 
 cut back to an upright lateral, as in figure 
 12. The slight bend will hardly show on 
 
 [18] 
 
the trunk after the permanent head is well 
 established. 
 
 Owing to the great susceptibility of 
 carob trees to rotting of the trunk and 
 branches by organisms that enter through 
 old wounds, careful training for young 
 trees is more important than for trees of 
 most other kinds. All temporary branches 
 should be removed before they are more 
 than about two inches in diameter at their 
 bases: there are usually enough small, 
 temporary branches along the trunk to 
 give it strength and cause the leader shoot 
 to be upright after any branches that are 
 
 this large have been removed. Further- 
 more, all permanent branches should be 
 well spaced so that they will not grow 
 against each other at their bases and make 
 large pruning wounds necessary when the 
 trees have become older. Such training 
 seems advisable even if cutting out crowd- 
 ing branches delays formation of an at- 
 tractive head for a year or two. Branches 
 on a carob tree tend strongly to over- 
 crowd. 
 
 Chinese Elm. Figure 13 shows two 
 Chinese elm trees, Ulmus parvifolia, 
 sometimes known as the evergreen elm. 
 
 Fig. 13. Chinese elms, Ulmus parvifolia. Tree at left trained by cutting away all but a few 
 branches at the top each year. Tree at right with temporary branches left distributed along the 
 trunk to strengthen it, but cut back each year to keep them out of the way. This tree could stand 
 against the wind without a stake more than two years earlier than tree at left. 
 
 [19] 
 
The tree at the right with the lower 
 branches left temporarily stood without 
 stakes at least two years sooner than that 
 at the left, which had all but a few shoots 
 at the apex removed each year. Owing 
 to frost damage to the top in the preced- 
 ing winter, the lowest branches of the 
 tree on the right grew too much during 
 the summer and should have been short- 
 ened-in. Branches were left too low for 
 street trees. Drooping branches of these 
 Chinese elm trees can grow even faster 
 than those of carob trees: mere cutting 
 off of the upright parts does not keep the 
 temporary branches small enough. They 
 should be cut back to a length of 12 to 18 
 inches at least once a year, or oftener. 
 When Chinese elm trees are pruned as 
 at the left in figure 13, they gain in height 
 a little faster than when temporary 
 branches are left, and the head begins 
 to develop sooner and may grow a little 
 faster; but the trunk is weak so that a 
 tree trained in this manner gives more 
 trouble than trees of most other kinds, 
 and may be blown over in spite of strong 
 stakes reaching well up into the head. On 
 the other hand, when carefully pruned 
 temporary branches are left along the 
 trunk from the time the tree is planted 
 until permanent branches are two or three 
 years old, the trunk gains strength much 
 more rapidly, while the head increases 
 in spread a little more slowly. Trained 
 in this way a beautiful head on a strong 
 trunk can be obtained with the Chinese 
 elm sooner than with most other trees 
 except a few species of Eucalyptus. 
 
 Pittosporum. In some species of Pit- 
 tosporum the branches come out in 
 whorls, sometimes ten or more at one 
 level. These spreading shoots interfere 
 with growth of the central upright shoots 
 and reduce the elongation of the central 
 leader more in some kinds than in others. 
 This tendency is striking in the tobira 
 pittosporum, causing it to be a low- 
 spreading shrub. Pulling off all shoots 
 but the central one from the same level 
 at each whorl when they are only about 
 
 one to three inches long causes a surpris- 
 ing increase in elongation of the central 
 stem, also in size of its leaves and, tem- 
 porarily, in its thickness. In its third year 
 after being transplanted at eight inches 
 in height, this species will be more than 
 five feet tall, while plants not having 
 these shoots pulled off will be 14 to 18 
 inches tall and as broad. Greater thick- 
 ness of the central stem is temporary. 
 Later increase in thickness from cambial 
 growth will be slow owing to lack of leafy 
 branches. 
 
 Young trees of the orangeberry pit- 
 tosporum, P. undulatum, also increase in 
 height considerably faster if the young 
 lateral shoots are pulled away from 
 around the central shoot after they come 
 from the bud. If all in each whorl are 
 pulled off until the trunk is three or four 
 feet tall, however, the trunk will be too 
 slender and difficult to keep straight. 
 Trees of this species and of tobira with 
 no branches left along the trunk tend to 
 sprout worse near the ground than trees 
 with at least a few branches left along 
 the trunk. To train a young orangeberry 
 pittosporum tree, or a tobira plant if one 
 should want to train it to a small tree, 
 the better plan is to remove all but one 
 or two lateral shoots in each whorl soon 
 after they emerge from the bud, leaving 
 shoots in successive whorls up the trunk 
 in such positions that they will be ar- 
 ranged spirally on the trunk. As these 
 shoots, temporary branches, grow and 
 branch, they will need some pruning of 
 upright parts to spreading laterals so that 
 they will not weaken the leader and its 
 higher branches, by shade or otherwise, 
 and will not become too large and leave 
 too large wounds when they are cut off 
 after the trunk has become strong enough 
 to support a head of permanent branches. 
 The orangeberry pittosporum is easily 
 trained by this method to a tree with the 
 lowest permanent branches starting at 
 any desired height. Tobira trees are more 
 difficult. After the first few years, the 
 pruning necessary to change them from 
 
 [20 J 
 
Fig. 14. Sydney acacia, Acacia longifolia. A 
 tree three years old before and after pruning 
 at the end of the blooming season. Such severe 
 pruning does not prevent even young trees of 
 this species from blooming beautifully, if the 
 pruning is done just after the bloom each spring 
 and a leaf with its bud is left on each branch 
 stub. 
 
 their natural low, compact growth to an 
 upright form is apt to cause so much pro- 
 longed, succulent shoot growth that aphis 
 injury may be serious. New shoots on 
 branches of trees in these species tend 
 also to be in whorls. Usually one shoot 
 in the whorl greatly outgrows the others. 
 If one wants a shrub rather than a tree, 
 one can cut out the strong branches in a 
 whorl, leaving at least one of the weaker 
 ones with healthy leaves. The wounds will 
 not show, and after the pruning the plant 
 will not be changed much in appearance, 
 but will be smaller. The orangeberry pit- 
 tosporum eventually becomes very large, 
 but by such pruning it can be kept as a 
 shrub of moderate size, with its natural 
 appearance for many years, although a 
 tree pruned this severely will tend to pro- 
 duce no flowers or fruits. 
 
 Acacia. Figure 14 shows best pruning 
 of young trees of the Sydney acacia, 
 
 Acacia longifolia. This acacia tends to 
 gain height a little faster with all the trunk 
 shoots removed. Such pruning, though, 
 makes the trunk especially slender and 
 easily broken. The head develops so 
 rapidly that strong wind pressure is apt 
 to break the trunk unless a strong stake 
 extends well up into the head and tying 
 is with strong material at the top and at 
 a considerable number of positions along 
 the trunk. On the tree at left in figure 14 
 most of the lower branches are left but 
 are pruned back rather severely each 
 year, so that no one of them will take 
 dominance away from the leader. With- 
 out such pruning of the lower branches, a 
 Sydney acacia tree spreads out with a 
 number of trunks that bend to the ground 
 and form roots, so that eventually one 
 tree may cover a wide area with roots 
 at many positions. When trained upright 
 it may become a beautiful, low-spreading 
 tree. On the right in figure 14 is shown 
 this same tree after pruning. Each branch 
 has at least one leaf with its bud to grow 
 new shoots like those on the tree at the 
 left. The pruning was done at the end of 
 the blooming period because even such 
 young trees of this and some other Acacia 
 species bloom beautifully along the whole 
 length of each shoot. A young tree being 
 trained in this way is a beautiful bloom- 
 ing shrub during the years before the 
 trunk is strong enough for a permanent 
 head to be formed with the lowest 
 branches seven or eight feet from the 
 ground and the temporary branches re- 
 moved. Although leaving the lower 
 branches retards the upward growth of 
 Sydney acacias a little, it makes the trunk 
 straighter and strong enough to support 
 the head much sooner without a stake. 
 A tree of this species is at its best when 
 in a position where the low branches can 
 be left and all branches pruned somewhat 
 like those on the tree in the center each 
 spring as soon as the flowers have died. 
 If lower branches are to be kept alive, 
 the upper ones must also be pruned 
 severely each year. If pruning begins 
 
 [21 
 
early enough, this tree can be trained to 
 many other beautiful forms: against 
 walls, hedgelike along the ground, as a 
 rounded shrub, or in other ways. 
 
 Trees of a number of other Acacia 
 species can be trained to have a straight 
 trunk with the lowest branches seven feet 
 or more from the ground with much less 
 pruning and staking, but few are as dur- 
 able in heavy, wet soils and as free from 
 leaf abnormalities owing to soil condi- 
 tions as this Sydney acacia. 
 
 Victoria Tea. Plants of the Victoria 
 tea, Leptospermum laevigatum (myrtle 
 family), naturally grow long and some- 
 what viny with long, ropelike stem and 
 branch leaders, but of course can be kept 
 to low shrubs if pruning back begins 
 early enough. They are sometimes trained 
 to very beautiful small trees with slightly 
 pendulous branches. The trunk is slow 
 to become strong enough to support a 
 head, and it must be tied to stakes at fre- 
 quent intervals if it is to be kept straight. 
 Temporary branches below where the 
 head is to begin are best left to hasten 
 thickening of the trunk, but they will re- 
 quire pruning back to laterals at least 
 once a year. The leader also will require 
 shortening downward to upward-grow- 
 ing laterals after it has become taller than 
 the stake. This is to delay upward exten- 
 sion until the part left has become strong 
 enough to stand erect, and also to throw 
 more growth into the permanent branches 
 and keep the leader from making its 
 natural long, straggling growth. 
 
 A variety of this species known as 
 Compact is much slower in upward 
 growth. Left unpruned, its branches are 
 very thick along the trunk and tend to 
 outgrow it, so that the plant becomes a 
 compact rounded shrub. To make a small 
 tree of it, cutting off all branches but a 
 few at the top each year, causes the trunk 
 to gain height a little faster in the first 
 two or three years. However, leaving 
 some of the branches five or six inches 
 apart arranged spirally around the trunk 
 and cutting them back to spreading later- 
 
 [22 
 
 als each year makes the trunk more easily 
 kept straight, and seems to make it elon- 
 gate faster after the first few years. The 
 tree also will have a much more attrac- 
 tive appearance while it is being trained. 
 The ugliness of trees with only a few leafy 
 shoots at the top of a slender stem will 
 last longer for trees of this slow-growing 
 variety than for trees of the less compact, 
 more straggling variety. At least four or 
 five years longer will be required to ob- 
 tain a tree of this Compact variety with 
 the lowest branches seven or eight feet 
 from the ground than to obtain such a 
 tree in the other variety, or in most other 
 tree species. Leafless stubs should not be 
 left in pruning Leptospermum plants: 
 such stubs rarely send out new shoots but 
 die and leave wounds that distort the 
 trunk. 
 
 Melaleuca. The Melaleucae, another 
 group of plants in the myrtle family, in- 
 clude some beautiful trees such as M. leu- 
 cadendron, M. styphelioides, M. genisti- 
 folia, and others. These usually make 
 their strongest growth in the upper part 
 and are easily trained to have the lowest 
 branches start at any height desired, eight 
 feet or more from the ground. Temporary 
 branches left below this height will re- 
 quire shortening downward to spreading 
 laterals once each year or two, but are 
 more easily kept small enough than such 
 branches on many trees such as the carob, 
 and the trunk becomes strong enough to 
 support a free-growing head sooner than 
 that of many kinds. When these tempo- 
 rary branches are removed a straight and 
 most beautiful trunk shows, those of M. 
 leucadendron and M. styphelioides with 
 peeling, creamy-white flakes of velvety 
 bark. 
 
 Eucalyptus. Eucalyptus species com- 
 prise the greatest group of California 
 trees in the myrtle family. In a few of 
 these, especially the scarlet eucalyptus, 
 E. ficifolia, low temporary branches on 
 the trunk may require some cutting back 
 to spreading laterals to keep them from 
 shading and weakening shoots on the 
 
Fig. 15. Lemon eucalyptus (Eucalyptus citrio- 
 dora) cut back to far below any leafy branches. 
 It grew another good top from old buds near 
 the tops of these branch stubs. 
 
 leader. Trees of most of the other well 
 known species, as they grow in height, 
 tend to weaken or even kill off lower 
 branches. This is strikingly true of the 
 rosy-flowered E. sideroxylon, the Mulga 
 ironbark eucalyptus, on which the trunk 
 of an unpruned tree 25 or 30 years old 
 may have no branches alive below a 
 height of 20 feet or more. Pruning back 
 the top tends to keep these lower branches 
 alive longer, for a branch is not so easily 
 killed off once it has become an inch and 
 
 a half or more in diameter. Such cutting 
 back of the top of young trees of some 
 eucalyptus species is advisable to reduce 
 the danger of wind damage. 
 
 Trees of E. citriodora, the lemon euca- 
 lyptus, tend to kill off the lower branches 
 even much faster. A tree 25 years old and 
 40 feet tall or taller may have only a 
 tuft of leafy branches at the top and may 
 continue increasing in height and killing 
 off more branches for a considerable 
 number of years. Usually such trees are 
 grown where their tall, slender form is 
 wanted; but if one is wanted with the 
 branches starting at a height of eight to 
 ten feet, this can be brought about by 
 selecting about three branches starting 
 near that height and cutting the leader 
 back to the uppermost one of these 
 branches, then each year pruning back 
 a little any one of the three branches that 
 tends to outgrow the others very much, 
 always cutting the uppermost part of 
 such a branch back to an upward-grow- 
 ing lateral that will become the leader 
 for the branch. If these branches are not 
 cut back a little every few years, they will 
 kill off their lower laterals so that each 
 branch will become long and slender with 
 only a tuft of leafy lateral branches at 
 its top. 
 
 Unlike the Leptospermae, eucalyptus 
 trees have many old buds with living tips 
 in the bark. These old buds are usually 
 prevented from growing by the leafy 
 branches above them, sometimes 20 or 
 30 feet above them. If the tree is cut back 
 to below all leafy branches, as in figure 
 15, many shoots will start from old buds. 
 A hormone moving downward from the 
 leaves and opening buds is probably what 
 prevents the buds below them from grow- 
 ing, but this can hardly be what kills off 
 branches that have started ; nor can shade 
 be the cause, for isolated slender trees 
 show the same dying off of the lower 
 branches. We do not know the cause of 
 this. Branches behave as if their connec- 
 tion with the water supply in the trunk 
 were sealed off. 
 
 [23] 
 
LARGE CONIFERS 
 
 Trees in many species of large conifers, 
 especially most pine species, tend natu- 
 rally to maintain a central leader that is 
 much stronger in growth than any of its 
 branches and to have branches that 
 spread outward, so that lower ones do 
 not grow upward and damage branches 
 above them by shade. If such a tree must 
 have its lowest permanent branches eight 
 to ten feet from the ground, its lower 
 branches can be left temporarily and will 
 need little or no pruning to keep them 
 from weakening the leader and the per- 
 manent branches. (One pine species and 
 some incense cedars are exceptions to 
 this.) In fact, the ideal in training young 
 broadleaf trees to obtain a good leader 
 until permanent branches are formed, is 
 to force the temporary branches to grow 
 outward like those of a pine tree. On 
 conifers the temporary, lower branches 
 are cut off when the tree is tall enough to 
 be attractive without them. 
 
 Fig. 16. Beautiful deodar cedar (Cedrus deo- 
 dara) on broad lawn so that it can branch low 
 without being inconvenient or obstructing the 
 view of any important object. Such a situation 
 is best for the deodar cedar. 
 
 Fig. 17. A deodar cedar tree (Cedrus deo- 
 dara) that is very beautiful but reduces the 
 beauty of the house and grounds and makes 
 the rooms next to it too dark. It would still be 
 beautiful if all branches below A were removed 
 and branches left below B were cut back to lat- 
 erals at a length of 5 to 7 feet. 
 
 Italian Stone Pine. The Italian stone 
 pine, Pinus pinea, has a nearly flat top, 
 owing to the tendency of the branches, in- 
 cluding the lowest ones, to turn upward 
 and to grow more vigorously than the 
 leader. Yet once the head has been estab- 
 lished with the lowest branches at a con- 
 venient height, the tree is strikingly 
 beautiful. Like most pines, it thrives in 
 northern California. It seems more du- 
 rable in southern California than some 
 others. One would think that cutting back 
 the upper parts of lower branches to 
 spreading laterals would prevent them 
 from damaging branches above them by 
 shade and yet retain much of their leaf 
 surface to support growth of trunk and 
 roots. It should also keep them from be- 
 coming so large that too conspicuous 
 wounds would be left on the trunk when 
 they are cut off. However, we have not 
 had an opportunity to test such a practice 
 
 [24] 
 
Fig. 18. Deodar cedar (Cedrus deodara) with 
 many lower branches removed to let more light 
 into the house. It might be more beautiful if the 
 lowest branch on the left were cut back enough 
 to make it a little shorter than the next branch 
 above it, and if several short branches had been 
 left below it on the right-hand side. 
 
 except in a small way, on trees that were 
 too large for good results when the trial 
 began and were removed before the effect 
 of the pruning could be learned. In parts 
 of Europe these lower branches are cut 
 off for fuel while they are small. The 
 leader will be temporarily more slender 
 because of the reduced leaf surface sup- 
 porting its growth, but will probably be 
 strong enough to support the branches 
 left at its top. For a time a young tree 
 so pruned will look ungainly with a 
 spreading head on top of eight to ten feet 
 of bare slender trunk. 
 
 Incense Cedar. On some trees of the 
 incense cedar, Libocedrus decurrens, if 
 the lowest permanent branches are to be 
 eight to ten feet from the ground, the 
 lower temporary branches may need at- 
 tention. The branches may be upright and 
 very close to the trunk. One or more of 
 them may grow so vigorously that they 
 
 become about as tall and have about as 
 many branches as the leader. Next to 
 them nearly all branches of the leader 
 will be killed off. If such a branch is cut 
 off a large wound is left and the head is 
 distorted, and the part that was shaded 
 by such a branch will have no living 
 branches. This condition can be easily 
 prevented by cutting back all temporary 
 branches to spreading laterals before 
 they become tall enough to be harmful. 
 The laterals do not have a strong tendency 
 to turn upward or to grow as rapidly as 
 the branch leader, and so if such cutting 
 back of temporary branches is done once 
 in two or three years, they will not be- 
 come injuriously large. Branches of some 
 trees of this species have spreading tend- 
 encies like pine or redwood trees. On 
 such trees lower, temporary branches 
 may require little or no attention until 
 they are cut off, if they are to be cut off. 
 
 Fig. 19. Deodar cedar (Cedrus deodara) 
 pruned rather high. It would be a little more 
 beautiful if it had shortened branches extend- 
 ing 6 or 7 feet below the lowest it now has. But 
 with its rounded head it is no less attractive than 
 any other kind of tree pruned this high. 
 
 [25] 
 
Deodar Cedars. A tree of this spe- 
 cies, Cedrus deodara, is most beautiful 
 when grown on a large lawn where, with- 
 out obscuring the view of more impor- 
 tant objects such as a dwelling or other 
 building, it can be left unpruned, with its 
 lowest branches spreading out on or near 
 the ground, as figure 16 shows. It thrives 
 in all California except in rather high 
 mountains, and is a more healthy, de- 
 pendable tree than many others in south- 
 ern California, where it is often planted 
 in lawns as small as 50 feet wide in front 
 of a dwelling. If branches are left from 
 the ground up, or nearly so on such lots, 
 little open lawn is left and there is no 
 impressive view of the dwelling, as figure 
 17 shows. If enough lower branches be- 
 low A were cut off for the house to be 
 seen well, the head with its broad-spread- 
 ing lower part and pointed top would be 
 somewhat unattractive in appearance. 
 The tree is beautiful as it stands, but be- 
 sides detracting from the appearance of 
 the house and grounds, it shades the win- 
 dows too much. If, besides cutting off 
 all branches below A, those left below B 
 were cut back to laterals so that they 
 would average about half the length of the 
 branch at B, the lowest being cut the 
 shortest, the tree would be nearly as beau- 
 tiful as it is now, and the combined effect 
 of tree, house, and grounds, much more 
 beautiful than it is now. The trees in fig- 
 ures 18 and 19 have been pruned up be- 
 cause they shaded the windows too much 
 
 and interfered with passage around the 
 houses. That in figure 18 would be more 
 beautiful if the lowest branch at the left 
 were cut back to a lateral so that it would 
 be a little shorter than the next one above 
 it, and if a few shortened branches had 
 been left on the right-hand side. 
 
 If these fine, sturdy trees are to be used 
 in front of dwellings on small lots, per- 
 haps the best way to train them will be 
 to begin shortening-in the lowest branches 
 when they become five or six feet long, 
 cutting them back this short each year, 
 never leaving stubs projecting beyond 
 the lateral, always cutting close to a 
 lateral. Branches up to a height of about 
 15 feet should be kept from becoming 
 more than about six to seven feet long. 
 By the time the tree is about 30 feet tall, 
 enough lower branches should have been 
 removed to expose a good view of the 
 residence and other parts of the ground. 
 This removal of branches should be 
 through a period of several years, those 
 on the lowest four or five feet of the trunk 
 when the tree is 15 to 20 feet tall, so that 
 the lawn will do well under it. 
 
 Fortunately lateral branches remain 
 healthy, even on branches of rather old 
 deodar trees. If one was not trained while 
 young, it can still be trained to the form 
 wanted after it has become large. From 
 most such trees, lower branches that are 
 not to be cut off can still be cut back to 
 healthy laterals at a length of five or seven 
 feet. 
 
 PRUNING TO CONTROL SIZE 
 
 Cutting away old branches, keeping trees below 
 natural height, and pruning down for better flower- 
 ing are the main control problems. 
 
 CUTTING OLD BRANCHES 
 
 If a tree is in a situation where the 
 head can increase in size indefinitely 
 without injuring other parts of the plant- 
 ing or becoming dangerous to the house, 
 it may need very little pruning after its 
 temporary branches have been removed. 
 
 There may be weak, crowding, broken, 
 or dead branches to cut out. Some of the 
 lowest branches that are expected to be 
 permanent may droop enough to be in 
 the way or to become weak and unattrac- 
 tive owing to shade from above. 
 
 When a large, rather old branch is cut 
 
 [26] 
 
off, the wound may not be covered by 
 new, protecting bark soon enough to pre- 
 vent rotting of the exposed wood and en- 
 trance of heartrot organisms deeper into 
 the trunk. Stubs several inches long do 
 not become covered until the tree has 
 grown a layer of new wood more than 
 that thick. Almost certainly they will rot 
 during that time, and the rot will get deep 
 into the wood. 
 
 On the upper side of a branch being 
 removed, the saw should always start 
 close against the bark of the trunk or 
 branch from which it is being cut. A 
 smaller wound will be made if it slants 
 outward a little, more nearly directly 
 across the branch, as at the right in figure 
 20. The wound will be much larger if 
 the cut is made parallel to the trunk, as 
 at the left in figure 20, but callus will 
 grow across it faster, so that it will heal 
 about as soon and the healing will be 
 more even, as figure 21 shows. Figure 22, 
 taken five years after figure 20, nearly 
 six years after the wounds were made, 
 shows both wounds almost completely 
 covered. There may be little difference in 
 merit of the two methods of cutting. Back 
 of the uncovered slit in both is a pocket 
 that will hold a considerable amount of 
 water. The larger pocket will be under 
 wounds like those at the left in figures 
 20-22. Unless wood of the tree concerned 
 is known to be highly resistant to rots, 
 such a slit should be opened farther down- 
 ward to the bottom of the pocket so all 
 water will drain out quickly. Wounds like 
 this should be kept covered thoroughly 
 but thinly with some protecting sub- 
 stance, such as an asphalt preparation or 
 a mixture that contains a disinfectant. 
 
 PREVENTING FULL GROWTH 
 
 If a tree is in a situation where it 
 should be prevented from becoming as 
 large as it would naturally grow, this can 
 be done most economically and without 
 destroying its natural beauty by cutting 
 the longest branches back to laterals. Of 
 course, the farther back on each branch 
 
 the cut is made, the fewer cuts will be 
 required. But on trees of most kinds, if a 
 branch is cut back to where its diameter 
 is rather large and the lateral is small, 
 weakened by shade, the cut end will be 
 very slow in being covered by new wood; 
 and the tree will be unattractive in ap- 
 pearance until the weak laterals have been 
 invigorated and have made a consider- 
 able amount of growth. By making more 
 cuts but removing less of each branch 
 and of each large lateral, a good pruner 
 can remove much of the top and still leave 
 the tree looking natural, looking un- 
 pruned. This ideal can be realized much 
 better if annual cutting back of branches 
 to healthy laterals begins before the tree 
 has become much larger than is wanted. 
 
 Branches on trees of some kinds be- 
 come long rapidly and are brittle and 
 easily broken by wind or by weight of 
 fruits and leaves. This is especially true 
 of the swamp mahogany, Eucalyptus 
 robusta. Its foliage, its abundance of 
 creamy flowers, and its redwood-like, 
 rough-barked trunk are beautiful, and it 
 is more tolerant than most kinds in com- 
 pact, wet soil ; but its annual shoot growth 
 is so long and brittle that if the branches 
 are not shortened-in each year before the 
 fruit is heaviest and the winds strongest, 
 the tree will become unattractive in ap- 
 pearance, because of broken branches. 
 On this account the tree is rarely planted. 
 Yet some very beautiful trees of it may 
 be seen under telephone or power wires, 
 where the branches have been cut back 
 annually to keep them below the wires. 
 
 Sometimes cutting back branches to 
 below all healthy laterals is necessary. 
 After such severe cutting, new strong 
 shoots will be largely from old buds with 
 their tips in the bark. Trees of some kinds 
 have no such old buds, and those of other 
 kinds, such as the Arizona ash, do not 
 have them distributed well along all 
 branches, so that some branch stubs may 
 produce no shoots and the tree so pruned 
 may become highly lopsided. 
 
 [27] 
 
PRUNING DOWN FOR 
 BETTER FLOWERING 
 
 Some deciduous trees grown for spring 
 flowers may be more desirable if they are 
 kept smaller and less straggling than they 
 would naturally become. This is usually 
 true of flowering peaches and plums, in- 
 cluding the red-leaved, double-flowering 
 hybrid known as Prunus Blireana. If trees 
 of these kinds are cut back severely at 
 the end of the blooming period, they 
 grow long, usually branched shoots that 
 often bloom throughout their length in 
 the following spring. In California, espe- 
 cially in coastal districts, such long shoots 
 will bloom later than less vigorous ones 
 on the same tree, because of their longer 
 chilling requirements. Such pruning, 
 therefore, causes the tree to be in bloom 
 during a longer period, first in spring on 
 the shorter, weaker shoots and last on 
 the longest, most branched shoots. The 
 warmer the preceding winter has been 
 and the later the growth during the pre- 
 ceding summer, the longer the spring 
 bloom will last. If other conditions are 
 favorable, lateness of summer growth will 
 be determined by severity of spring 
 pruning. Part of the pruning of such trees 
 can be the cutting of blooming shoots for 
 house flowers, pruning being completed 
 at the end of the blooming period or 
 when, with only scattered bloom, the tree 
 has become unattractive. 
 
 If the variety is one whose blooming 
 is too greatly delayed and straggling after 
 warm winters, or one that sheds its flower 
 buds or its flowers before they are fully 
 open, severe pruning at any time, by in- 
 creasing the chilling requirement, may 
 accentuate this unsatisfactory behavior. 
 (See "Choosing Times to Prune," p. 9.) 
 
 Trees in most species of flowering 
 cherries are best with little pruning; for 
 they do not set many flower buds on the 
 long shoot growth that severe pruning 
 induces. 
 
 Some jacaranda trees bloom heavily 
 in early summer to midsummer after 
 
 Fig. 20. Pruning wounds beginning to heal. 
 Wound at left was made by sawing nearly par- 
 allel with trunk and chiseling out the base. 
 Wound at lower right was made by slanting 
 outward from the top, making a much smaller 
 wound. 
 
 dropping all their leaves and are slow to 
 put out new leaves after they stop flower- 
 ing. Thus they present a bare, unattrac- 
 tive appearance in midsummer. Others 
 bloom without dropping all their leaves 
 and are never without leaves in the dis- 
 trict along the southern California coast 
 where the winters are warm. Some trees 
 bloom with their leaves and are without 
 a leafless period during the first four or 
 five years of blooming, but when older 
 have a leafless period following the bloom 
 each year. 
 
 Attempts were made to keep such trees 
 from going into an annual leafless pe- 
 riod by pruning enough to keep their 
 annual shoot growth about as vigorous 
 as it was when they were blooming with 
 the leaves. This pruning reduced flow- 
 ering greatly, but the trials were not 
 extensive enough for completely convinc- 
 ing evidence. The results suggest that a 
 jacaranda tree should not be pruned 
 much unless unshapely or crowding 
 branches make some cutting necessary. 
 Possibly light cutting back annually soon 
 after the bloom to keep a tree head small 
 enough for the space available would not 
 reduce flowering appreciably. 
 
 [28] 
 
Fig. 21 (left). The same wounds after 2 years of healing. Both are being covered by new wood 
 and bark. Fig. 22 (right). Wounds as in fig. 20, but 5 years later. They are being covered about 
 equally well. Each has a slit left through which water may enter, and a cavity between the new and 
 old wood in which water may stand and possibly cause rotting. The cavity is larger under the 
 wound at left. 
 
 PRUNING COLUMNAR TREES 
 
 Beautiful open effects can be achieved by cutting 
 back to laterals, training to a central leader. Avoid 
 clipping. 
 
 Small upright trees with leafy branches 
 from the ground up may give a beautiful 
 effect in formal plantings and in proper 
 relation to architectural detail, if they are 
 not forced into unnatural formality. In 
 parts of California, especially in the Los 
 Angeles area, however, many trees thus 
 used are trained to unnatural, spectacu- 
 lar ugliness like that in figure 23. Ap- 
 parently the gardener thinks of what a 
 neat job of clipping he does and not of 
 what he makes the tree, or the home, 
 look like. He usually does not intend to 
 make the trees look as pudgy as those in 
 figure 23, but clipped trees must be a 
 little larger after each clipping unless one 
 cuts into old, hard wood of the stubs. 
 
 A tree trained to a central leader by 
 cutting upward-growing branches back 
 to spreading laterals and kept open 
 enough for small areas of trunk to be 
 seen between some of the branches, and 
 for all branches to be free from stubs or 
 dead wood, will be much more beautiful 
 
 Fig. 23. Eugenia tree (Eugenia paniculata) 
 made painfully ugly by clipping instead of 
 pruning back to laterals. 
 
 L 29 
 
and can be easily kept at the height and 
 degree of slenderness wanted. 
 
 Arborvitaes. Some varieties of the 
 arborvitaes, Thuja orientalis and T. occi- 
 dentalism and varieties of false cypress, 
 Chamaecyparis spp., are beautiful colum- 
 nar trees. In some varieties, however, 
 lower branches on trees left unpruned 
 will grow up on the outside and shade 
 out most of the branches that start higher 
 on the leader, so that the tree comes to 
 be composed of many stems, the inner 
 ones containing many dead branchlets 
 except at the top. The slender outer stems 
 will have leafy branchlets along the out- 
 ward sides. The weight of these branch- 
 lets, especially if they are wet, eventually 
 bends the slender stems downward to the 
 ground or breaks them. This exposes an 
 ugly lot of bare stems and dead branch- 
 lets. By cutting back all upright branches 
 to spreading laterals, trees of these varie- 
 ties can be easily trained to a central 
 leader form with spreading, short 
 branches so spaced that few if any are 
 killed by shade. All parts then can be 
 readily washed clean with the hose. 
 
 The trees in figure 24 are of a rather 
 strong-growing variety of Thuja orien- 
 talis. The upper one was pruned to a 
 central leader beginning after the lowest 
 branches had become too tall for best re- 
 sults. The only pruning was a cutting of 
 upright branches down to spreading 
 laterals and cutting out of some branch- 
 lets from thick tufts. The tree is more 
 open and shows more of the trunk than 
 the figure indicates. It is too broad for 
 some positions, but this can be easily 
 remedied by cutting the longest spread- 
 ing branches back to healthy laterals. 
 
 The lower tree has made a flush of 
 new growth after being clipped by the 
 method practiced by some gardeners. 
 This clipping tends to prevent the outer 
 branches from becoming heavy enough 
 to break over. It does not prevent the 
 growth of a considerable number of stems 
 from near the base of the trunk that may 
 become nearly as tall as the central part 
 
 Fig- 24. Oriental arborvitae (Thuja orientalis), 
 upper pruned to a central leader, lower clipped 
 back to a stiff, woody surface covered by a 
 recent growth flush. 
 
 [30] 
 
Fig. 25. Young Italian cypress, Cupressus 
 sempervirens. Branches breaking over as here 
 are often controlled by surrounding wires at 
 several positions, making a compact, ugly bun- 
 dle, without any of the character of the above. 
 This tree is easily trained to a central leader. 
 
 of the tree ; nor does it prevent the shad- 
 ing to death of many branchlets that start 
 from the inner stems. The branches be- 
 come so close-fitting that dead wood and 
 leaf material accumulates between them 
 and is hard to dislodge. It is without the 
 appearance of sturdiness that glimpses of 
 a strong central trunk give, is too stiff 
 and unnatural in appearance. 
 
 The gold-edged variety of this oriental 
 arborvitae, Beverly Hills, is easily trained 
 to a natural-looking columnar form by 
 cutting back upright branches to spread- 
 ing laterals and is one of the most beau- 
 tiful of trees for such use. 
 
 Italian Cypress. A special form or 
 variety of the Italian cypress, Cupressus 
 sempervirens, can be used in many ways 
 in the landscape and, if pruned wisely, 
 is excellent where columnar trees are 
 
 wanted. Many lower branches grow up 
 around a number of inner ones, one of 
 which might be the leader, and thus shade 
 out all lateral growth on the inner 
 branches and on the inner side of the 
 outer ones. These lower branches are 
 longer and more slender than branches 
 on most other kinds and break over 
 worse. In figure 25, branches on a rather 
 young tree are breaking over. Sometimes 
 such branches are prevented from break- 
 ing over by wires around all the branches 
 at several positions. A tree of this cypress 
 tied up in this way will have especially 
 large quantities of dead material crowded 
 between the inner stems. Unlike the tree 
 in figure 25, which has at least some un- 
 evenness of surface, some character, 
 these trees after being tied up into tight 
 bundles are usually kept clipped smooth 
 and characterless and are sometimes even 
 clipped flat across the top. 
 
 This cypress is easily trained to a cen- 
 tral leader with short branches by cutting 
 upright branches back to the short 
 spreading laterals. These spreading 
 branches can be so spaced that pleasant 
 shadows and glimpses of the trunk show 
 between them, and all dying foliage can 
 be easily washed out with the hose. The 
 tree can be easily kept at any height 
 wanted by cutting the leader back to up- 
 right laterals, and in the next year cut- 
 ting this back to another such lateral that 
 is nearest to being a direct extension of 
 the trunk upward. The smaller this cy- 
 press tree must be kept and the more 
 severe the pruning required, the brighter 
 the branch ends will be and the less old, 
 dying, gray foliage there will be showing. 
 If the tree is in a position where it can 
 become 15 to 20 feet tall, branches start- 
 ing at carefully selected positions, rather 
 high along the trunk, may be permitted 
 to grow long enough to break over in 
 pleasant curves, as figure 26 shows. If 
 any of them are too long when they break 
 over, they can be cut back to laterals 
 where the wound will not show. 
 
 [31] 
 
Yews. The Irish yew, a columnar form 
 of the English yew, Taxus baccata, may 
 be among the most beautiful of small 
 trees, both in color and form. When un- 
 pruned it is very beautiful during the 
 first few years of its growth, but as it 
 grows older branches starting at the base 
 keep growing upon the outside of the 
 head and eventually bend outward from 
 their weight. If it is wired up and clipped 
 it comes to have a pudgy, barrel- or hogs- 
 head-like appearance, worse than the 
 eugenias in figure 23. If it is not wired 
 or pruned, the outer branches will bend 
 far over, some to the ground, some at 
 different angles; although ungainly for 
 a time, it may form a good spreading 
 shrub. Even so, it will not be more at- 
 tractive than the common English yew 
 or the Japanese yew, which do not go 
 through a period of ungainliness. 
 
 The greatest value of the Irish yew is 
 in situations where columnar plants are 
 most suitable. Training it to a single 
 trunk, a central leader, requires more 
 careful attention than with other colum- 
 nar trees. If each upright branch is cut 
 down to the lowest spreading one, the 
 tree will be too slender, especially in the 
 upper part. This is because pruned 
 branches on trees of this variety grow 
 slowly. If some branches are not cut back 
 until they are a foot long or a little longer, 
 the tree head will not be so slender or 
 have such a long point at the top, and 
 will be more beautiful. By careful cutting 
 or pinching back of branches at different 
 lengths, a central-leader form with some- 
 what spreading branches can be main- 
 tained, and the surface of the head kept 
 irregular so that the beautiful green of 
 its foliage is enriched by full play of light 
 and shadow. 
 
 Trees of other species in the yew fam- 
 ily, especially Podocarpus macrophylla, 
 can be trained for formal positions, but 
 not by merely cutting branches back to 
 laterals. They do not have enough 
 branches. Some shoots must be cut back 
 leaving stubs with six to ten leaves and 
 
 as many buds, several of which will grow 
 and increase the number of branches. 
 The branches should be pruned individ- 
 ually, however, and not merely clipped to 
 a flat surface. 
 
 Incense cedar. Some forms of the 
 incense cedar, Libocedrus decurrens, 
 tend to be compactly upright and may 
 be useful as columnar trees where size is 
 wanted. A branch starting near the 
 ground may become as tall as the leader ; 
 whether it forms nearly half of the tree 
 with its lateral branches or less than a 
 third, the tree head will be symmetrical, 
 almost cylindrical, too compact for its 
 greatest beauty. 
 
 A more beautiful head is formed, even 
 for a columnar tree with permanent 
 branches starting at different levels from 
 the ground up, if from the time the tree is 
 planted, upright branches are headed back 
 to laterals and small branches are thinned 
 out enough for the trunk to be seen. A tree 
 is still unattractive if it is thinned out 
 nearly to the top, with the top foot or two 
 
 Fig. 26. Italian cypress trees (Cupressus sem- 
 pervirens) permitted to become rather tall, but 
 trained to a single central leader with short 
 spreading and out-curved branches. 
 
 [32] 
 
left so compact that little light can be seen 
 through it. The same is true if the lowest 
 part is left too compact for the trunk to 
 be seen. Slight glimpses of the trunk at 
 any part of its length should be possible. 
 
 The tree tends to grow taller than may 
 be wanted, even when adjacent to large 
 buildings, but it can easily be kept down 
 to a height of 20 to 25 feet and yet look 
 natural. Branches near the top are often 
 nearly as upright as the leader shoot, so 
 that cutting back the leader will not cause 
 the tree to lean if the branch chosen is 
 the one that is most nearly in a straight 
 line with the stem. Care, of course, should 
 be exercised to keep such a columnar tree 
 from becoming flat across the top, al- 
 though more than one point at the top 
 may not be unattractive. The smaller the 
 tree is to be kept, the more frequent the 
 pruning must be to keep it attractively 
 open throughout its height. 
 
 Eugenia. The tree in figure 23 (p. 29) 
 is an Australian brush cherry eugenia, 
 Eugenia paniculata australis, formerly 
 
 known here as E. myrtijolia. Trees of this 
 species, permitted to grow freely to their 
 natural form, may be very beautiful. The 
 young, healthy, unpruned tree always is 
 attractive. Yet it probably exhibits more 
 ugliness in parts of California than any 
 other plant grown, owing to the clipping 
 that it receives. The tree has a strong 
 tendency for upright branches to become 
 long and slender and to break over under 
 the weight of wet leaves. To prevent this 
 and keep it attractive against a building, 
 upright branches may be cut back to 
 spreading or preferably drooping later- 
 als. When the tree promises to become 
 too tall, it can be kept low by cutting the 
 leader back to an upright branch. How- 
 ever, there usually is more than one up- 
 right branch starting at the same level 
 near the top. To keep the top of a colum- 
 nar tree looking natural, like that of a 
 young tree, is more difficult with this eu- 
 genia than with the conifers discussed in 
 this section. For good results pruning 
 must be more frequent than once a year. 
 
 PRUNING ORNAMENTAL 
 SHRUBS 
 
 Carefully done, even severe pruning will not dis- 
 turb natural appearance. Time to prune depends on 
 flowering, fruiting habits. 
 
 No attempt will be made here to recom- 
 mend exact methods of pruning each im- 
 portant kind of shrub. Too many dif- 
 ferent methods are suitable for any one 
 kind in different situations. The oleander, 
 for example, can be trained to a small 
 tree, with a good deal of cutting or pull- 
 ing of suckers from around the base of 
 the trunk and by leaving shortened tem- 
 porary branches along the trunk until it 
 is strong. It also can be trained into a 
 large shrub with branches shortened to 
 laterals each year. Some oleander varie- 
 ties can be trained into small shrubs with 
 only young shoots left each spring, shoots 
 
 that have recently started at the ground 
 level, all older parts being cut to the 
 ground. Again, nearly all branches can 
 be kept and trained flat against a wall 
 or a fence. Pruned by any of these meth- 
 ods the oleander can be a beautiful 
 blooming ornamental. Some varieties 
 may not bloom after the severe pruning 
 if only young suckers are left; others, so 
 pruned, will start blooming later in sum- 
 mer than if pruned little but will bloom 
 about as long. 
 
 Nearly all these methods can be used 
 for at least some varieties of the common 
 crape myrtle, Lager strcemia indica. 
 
 [33 
 
Shrubs of many other species can be very 
 beautiful when pruned little and per- 
 mitted to become large, or when pruned 
 severely and kept small. Some varieties 
 of cotoneasters may be beautiful when 
 trained low by severe pruning at the 
 proper time or, by contrast, when all 
 lower branches are cut off and all leaves, 
 flowers, and fruits are borne high enough 
 to let light into a window or to clear a 
 doorway. Cotoneasters are beautiful also 
 when trained flat against a wall with leafy 
 fruiting branches from the ground up. 
 
 Some shrubs, such as species of Phila- 
 delphus, mock orange, inappropriately 
 also called syringa by some, and species 
 of escallonia — Escallonia floribunda, E. 
 montevidensis and E. organensis — have 
 graceful, spreading branches of moderate 
 size, but they send up stiff watersprouts 
 
 that bloom a little later in larger, more 
 conspicuous clusters. If such a shrub is 
 in front where graceful form is most im- 
 portant, the young watersprouts may be 
 broken off before they become conspicu- 
 ous; but if the shrub has graceful plants 
 in front of it, the watersprouts may be 
 left for their flowers. 
 
 The beautiful glossy abelia, Abelia 
 grandiflora, is usually best trained to em- 
 phasize its naturally graceful arching, by 
 merely cutting out at the ground branches 
 that have become weak and stiff and suck- 
 ers that grow up above the more pleas- 
 antly arched branches of moderate size. 
 But sometimes a beautiful effect is ob- 
 tained by permitting some of the tall, stiff 
 suckers to stand against the corner of the 
 house with branches of smaller size arch- 
 ing outward in front of them. 
 
 Fig. 27. At right, a shrub of red escallonia (Escallonia rubra) pruned severely in midsummer 
 during a lull in blooming, when old flower stems were unattractive. The pile of prunings at left 
 contains more than half the leafy shoots that were on the bush, and yet because all cuts were to a 
 leafy shoot, the bush does not look pruned. 
 
 [34 
 
KEEPING SHRUBS 
 LOOKING UNPRUNED 
 
 Most kinds of good shrubs grow in such 
 a way that they can be pruned severely 
 without being made to look pruned, 
 even immediately after the work is done. 
 Such results are accomplished by cut- 
 ting out branches close to the stem or 
 at the ground, and especially by cutting 
 branches back to laterals at which the 
 wound is hidden by leaves, never clipping 
 as a hedge is clipped, never leaving stubs. 
 Clipping causes growth of many closely 
 packed branches and makes the shrub 
 stiff and uninteresting. Figure 27 shows 
 a shrub of the red escallonia, Escallonia 
 macrantha (known also as Escallonia 
 rubra), pruned severely in midsummer, 
 
 i &K, * | ' y s r * ^ J^ « 
 
 mm£ 
 
 Fig. 28. Blueblossom ceanothus (Ceanothus 
 thyrsiflorus) pruned in early summer soon after 
 the bloom. Prunings show in the pile at right. At 
 least three-fourths of the leafy shoot growth of 
 the preceding year was cut without leaving the 
 bush looking pruned or stubby. Some of the 
 bareness of the lower parts of the branch lead- 
 ers might have been prevented if pruning had 
 begun when the bush was younger. 
 
 the pile of prunings showing at the left. 
 Half or more of the leafy shoots have 
 been removed and yet the shrub does not 
 look pruned, is as graceful and natural 
 as before the pruning, and yet is much 
 smaller. Pruning twice a year is required 
 to keep it small enough for this position. 
 Wounds were made where they would be 
 hidden by leafy shoots. 
 
 Keeping the shrub looking young and 
 unpruned is more readily accomplished 
 on branches that are only three to five 
 years old and that started from the 
 ground, branches that have not accumu- 
 lated too many pruning wounds. Cutting 
 out some of the oldest branches at the 
 ground each year or two is advisable for 
 shrubs of many kinds. This is an espe- 
 cially large part of the annual pruning 
 of shrubs of kinds such as the glossy 
 abelia, Abelia grandiflora, with many 
 branches starting from the ground. 
 
 To keep living branches close to the 
 ground requires especial care for shrubs 
 of some kinds. On shrubs such as the Vic- 
 toria tea, Leptospermum laevigatum, and 
 some other species of this genus, shoots 
 will not grow from old wood or from the 
 roots, and few if any will grow from such 
 wood or roots of most ceanothus species, 
 inadvisedly called wild lilacs. Leafless 
 stubs of wood two or three years old or 
 older will not grow shoots but will die. 
 And as these shrubs grow taller, low 
 branches die off. Figure 28 is a bush of 
 Ceanothus thyrsiflorus, blueblossom cea- 
 nothus, pruned severely at the end of the 
 blooming season over a period of several 
 years; the pile of prunings at the right 
 shows how severely. Yet this has not 
 caused new laterals to start low on the old 
 branches where other laterals have died 
 off. The beautiful blue-flowered small 
 bush, Ceanothus impressus, which seems 
 more resistant to fungi in the soil in 
 southern California than most other cea- 
 nothus species, can be pruned severely 
 each year soon after the bloom by cutting 
 branches back to laterals as low as pos- 
 sible without leaving it looking pruned. 
 
 35] 
 
m^m 
 
 ff < ,~^ 
 
 ^.;'j*- 
 
 yf^pfr 
 
 Fig. 29. Pyracantha bush (Pyracantha sp.; firethorn) kept low # compact, unfruitful, and charac- 
 
 terless, by repeated clipping. 
 The pruning will cause even the weakest 
 leafy laterals to begin strong growth soon 
 but will not cause any new shoots to grow 
 from the trunk or the roots. To keep live 
 branches near the ground and the shrub 
 more beautiful, annual pruning should 
 begin before these lower branches die. 
 In parts of California, especially in the 
 Los Angeles area, one may see shrubs 
 with such natural grace as cotoneasters 
 and such strong beauty as pyracanthas 
 (firethorns) and Pittosporum Tobira, or 
 even Pittosporum undulatum, clipped 
 into smooth-surfaced globes, cubes, or 
 other unnatural forms. Some of the coto- 
 neasters and firethorns in some situations 
 bloom and fruit beneath the green sur- 
 faces in spite of such repeated clipping, 
 but many kinds so treated rarely if ever 
 flower. The clipping often given pyra- 
 canthas prevents their fruit from showing 
 in clusters along the branches in the beau- 
 tiful way that is natural to them, and may 
 cause them to bear very few fruits or 
 
 none. In figure 29 is shown a bush of 
 one of the most beautiful varieties of 
 pyracanthas. Repeated clipping by a very 
 conscientious gardener has robbed it of 
 all its beauty and prevented it from fruit- 
 ing. Yet all this clipping has not caused 
 the low branches to grow well. By cutting 
 the uppermost branches down to spread- 
 ing laterals and cutting those that may 
 spread too far away from the wall in to 
 branches against the wall, doing most of 
 this soon after the bloom so that branches 
 with fruit could be selected to remain, 
 the plant could have been kept low more 
 easily than by all this clipping. Further- 
 more, the lower branches could have been 
 kept alive so that in autumn and winter 
 masses of the beautiful fruit would show 
 from the ground to the top of the wall. 
 And at all times the beautiful foliage and 
 the play of lights and shadows in it and 
 glimpses of the wall through it, might 
 have made the plant seem a part of the 
 
 [36 
 
home and not just an antagonistic object 
 set down by it. 
 
 Other shrubs against a patio wall are 
 often clipped down to the level of the 
 wall at the top and to a flat surface on 
 the side. This tends not only to prevent 
 flowering but robs the shrub or small tree 
 of any special beauty it may have natu- 
 rally. For example, the Japanese vibur- 
 num, Viburnum japonicum, with its 
 large, deep green leaves and strong shoots 
 has, when growing naturally or pruned 
 in harmony with its nature, a rugged 
 beauty that is excelled by few plants, and 
 its broad heads of fragrant flowers in- 
 crease this beauty. Yet when so clipped 
 it neither blooms nor has the form that 
 makes it attractive. A design painted or 
 built into the patio wall or a rug or canvas 
 of appropriate color hanging on it would 
 seem much more beautiful than such de- 
 natured plants. By cutting branches back 
 to laterals without clipping off the ter- 
 minal of any shoot left, such a shrub could 
 be kept to the approximate height of the 
 patio wall and prevented from spreading 
 too far out into the lawn without pre- 
 venting it from blooming or destroying 
 its beauty of form. 
 
 Shrubs of some kinds, however, can- 
 not be so pruned that they look natural 
 immediately after the pruning. The poin- 
 settia, Euphorbia pulcherrima, for exam- 
 ple, seems best pruned back to stubs, each 
 with a few buds near the ground, or near 
 the top of a trunk if for some reason a 
 tall plant is wanted. When Chinese hibis- 
 cus (Hibiscus rosa-sinensis) branches 
 are pruned back to lower weak laterals, 
 these laterals do not show the increased 
 growth and branching, in the climate of 
 southern California at least, that such 
 weak branches would show after such 
 pruning on shrubs of many other kinds. 
 Possibly they are better in California if 
 pruned back more severely to stubs near 
 the ground. 
 
 The beautiful Brazilian glory bush, 
 Tibouchina semidecandra, sometimes 
 called pleroma, can be kept looking fairly 
 
 natural by cutting back to laterals in 
 spring. For best flowering and most at- 
 tractive summer foliage, however, more 
 severe pruning is advisable. Nearly all 
 leafy shoots may be cut back into wood 
 that is more than a year old. This will 
 cause new shoots, from old buds, to be 
 longer and with larger, more healthy- 
 looking, velvety leaves and perhaps larger 
 flowers. But the first flowers will open 
 later in summer than if the pruning has 
 been less severe. Bushes of this good 
 plant, even when growing in rather dense 
 shade, as on the north side of a building, 
 can be pruned severely without prevent- 
 ing abundant flowering during late sum- 
 mer and autumn, though the pruning and 
 the shade each delay the beginning of 
 blooming. Both keep the leaves attractive 
 later in autumn, however. Rather severe 
 pruning is advisable also to shorten the 
 brittle branches and so reduce the amount 
 of breakage by wind. 
 
 TIME TO PRUNE SHRUBS 
 
 Deciduous Shrubs. The best time to 
 prune a shrub will be determined partly 
 by its blooming habit. For deciduous 
 kinds that bloom in the spring, the best 
 time to prune is usually at the end of the 
 blooming period, so that the shrub will 
 have all of its natural gracefulness during 
 the bloom and the largest possible num- 
 ber of flowers. At this time new growth 
 will be rapid so that, if the pruning must 
 disfigure it somewhat, a natural attrac- 
 tive form will be regained soon. For 
 shrubs that make little or no leafy shoot 
 growth before the end of the blooming 
 period, delaying pruning until the end of 
 the blooming period will not reduce an- 
 nual growth appreciably. For those that 
 make a considerable amount of shoot 
 growth during the bloom, pruning at the 
 end of that period may reduce growth by 
 autumn slightly more than if it were done 
 before the bloom, before the stored food 
 supply had been depleted by growth and 
 flowering ; but the difference will be small 
 and of no importance. 
 
 37 
 
Broadleaved Evergreens. Some ev- 
 ergreen shrubs, also, bloom only in spring 
 and will have their most beautiful annual 
 flowering and summer form if their prun- 
 ing is done at the end of the blooming pe- 
 riod. If they are grown partly for their 
 beautiful fruits, as cotoneasters and pyra- 
 canthas are, one may dislike to reduce the 
 number of young fruits by pruning at the 
 end of the flowering period, and may pre- 
 fer to do the pruning when the fruit falls. 
 This, however, will remove flower buds 
 and thereby reduce the number of flowers 
 and fruits in the succeeding year. Further- 
 more, since the pruner cannot know at 
 fruit fall which branchlets will contain 
 or develop flower buds, he cannot choose 
 nonflowering branchlets to remove, as he 
 could at the end of the blooming period. 
 Shrubs of some kinds growing in full sun 
 can be depended upon to have flower buds 
 enough on all shoots each year. Such 
 shrubs in such positions may well be 
 pruned as soon as the fruit falls or be- 
 comes unattractive. The same shrub in 
 partial shade, however, may not form 
 flower buds on all shoots, and one may 
 want to prune only as soon as the flowers 
 have fallen so as to leave all good 
 branches that have young fruits on them. 
 If the flowering is late and the shrub is 
 growing where it must depend entirely 
 on water stored in the soil by winter rain- 
 fall, severe pruning of some ceanothus 
 species after the bloom has fallen may 
 prevent flowering in the succeeding year. 
 
 Cotoneasters and pyracanthas (fire- 
 thorns) often have nonfruiting shoots 
 or parts of shoots that grew after the flow- 
 ering period and that hide some of the 
 fruit clusters. Usually when the fruit be- 
 
 gins to color these shoots can be cut back 
 to expose the maximum display of 
 colored fruit, without causing appreci- 
 able reduction in the following spring 
 bloom. Pruning can then be completed 
 at the end of the blooming period. 
 
 Other kinds of evergreen shrubs, such 
 as escallonias, bloom either continuously 
 during the summer or at several intervals. 
 Perhaps the best single time to prune 
 these is either in early spring before 
 growth and flowering begin, say Febru- 
 ary or late January, or in early summer 
 at the end of the first flush of bloom. If 
 they are strong-growing varieties and 
 space is limited, more than one pruning 
 each year may be advisable. By midsum- 
 mer or a little later they may have be- 
 come less attractive, owing to accumula- 
 tion of old flower stems and seed pods, 
 and flowering may have become light. A 
 second, careful pruning that does not 
 leave the shrub looking pruned may actu- 
 ally improve its immediate appearance 
 and greatly increase its beauty after a 
 little leafy shoot growth has been made 
 and perhaps new and larger flower clus- 
 ters have appeared. Pruning more than 
 once a year, or even more than twice, 
 may be advisable for other strong-grow- 
 ing shrubs such as the very beautiful 
 Jasminum humile, Italian jasmine, but 
 they need never look pruned. 
 
 If a shrub is tender enough to be dam- 
 aged sometimes during winter nights in 
 the district concerned, rather severe 
 pruning in summer, especially after mid- 
 summer, may increase the danger of such 
 injury, reduce its winter resistance, by 
 causing it to grow too late. 
 
 To give directions for pruning each 
 kind of vine would be as unwise as to 
 give such directions for shrubs. Follow- 
 
 PRUNING ORNAMENTAL VINES 
 
 Best vines need heavy pruning. Learn what effects 
 to expect for your soil and degree of sunlight. 
 
 ing directions might keep a person from 
 using his own sense of beauty to fit his 
 vine into an interesting and original de- 
 
 [38] 
 
sign. To make such adjustments he must 
 know how his vine responds to the neces- 
 sary pruning in sun and shade. In rare 
 situations a vine can be permitted to make 
 unlimited growth, and training can be 
 merely a cutting out of drying parts and 
 tying the remainder in favorable posi- 
 tions. However, an unrestricted vine on 
 a dwelling may detract from its beauty 
 instead of increasing it. Much pruning 
 may be required to keep a vine in the 
 best position to enhance the beauty of the 
 home, and the pruner should know what 
 effect this pruning will have on growth 
 and flowering of his vine in the degree 
 of sunlight and depth and fertility of the 
 soil it has. 
 
 Vines of most weak-growing kinds will 
 not require enough pruning to influence 
 their flowering appreciably. Some of the 
 best, however, are strong-growing and 
 require much pruning unless available 
 space is great. 
 
 Wistarias. The Chinese wistaria, Wis- 
 taria sinensis, although it is without 
 leaves in the winter and will survive and 
 flower well as far north as New York, is 
 one of the best of these strong-growing 
 kinds, one of the few best vines, weak or 
 strong, for all of California. Its beauty 
 is often impaired by its being left un- 
 pruned, to form a brush pile on the house. 
 And it may injure the roof, by shoots 
 that grow under shingles, tiles, or other 
 material, and expand until the material 
 is broken. Its shoots should be kept off 
 the roof. If a large wistaria vine is wanted 
 on the house, it is better fastened to a 
 support at the height wanted and spread 
 outward away from the house. Wistaria 
 branches directed outward from such a 
 support soon have strength enough to 
 hold their positions with no other support 
 and are more beautiful than branches tied 
 down, as on an arbor. With staking and 
 much pruning in early years, the wistaria 
 can be trained as a low tree that will 
 eventually stand without a stake. Nearly 
 all buds on vines of either the white or 
 the purple form of this species are flower 
 
 buds, whether the vine is grown in full 
 sun or in a position where no direct sun- 
 light ever reaches it. And pruning much 
 more severe than is likely to be given 
 will not prevent the formation of flower 
 initials in nearly all buds. Although a 
 vine left unpruned until it is 10 or 12 
 years old may cover a space 30 feet 
 square or greater, it can be held down 
 by pruning to a space six by 12 feet and 
 will flower as well as if left unpruned 
 or better, in longer clusters. 
 
 The best time to do the heaviest prun- 
 ing is at the end of the spring blooming 
 period, but the vine will make good 
 growth and flower well in the following 
 spring even if this pruning is done sev- 
 eral weeks later, after new shoots have 
 become two or three feet long. Flower 
 buds are borne on two kinds of shoots: 
 (1) A flower bud produces in spring a 
 shoot with several leaves and a flower 
 cluster at its end. Then during the sum- 
 mer a flower bud forms in the axil of 
 each of these leaves except the weakest 
 at the base of the little shoot. Such short 
 flowering shoots will be called spurs in 
 this discussion, and buds on them will 
 be called spur buds. (2) Long shoots 
 grow from basal buds of spurs or shoots 
 of the preceding year or from older buds, 
 and these shoots, unless they are from 
 such dense shade in the interior of the 
 vine that leaves do not develop normally, 
 also tend to develop flower buds at all 
 leaves except small basal ones. 
 
 In southern California at least, where 
 the winters are very warm, buds on long 
 shoots tend to open a little later in spring 
 than buds on spurs. Severe pruning 
 causes the growth of more long shoots. 
 On a vine pruned very severely there may 
 be so many of these long shoots that pull- 
 ing off some, especially those starting 
 deep in the shade, may leave it more at- 
 tractive in appearance. However, a rather 
 large number of long shoots may help 
 to give a longer, more attractive bloom- 
 ing season in the following spring. On 
 one of these long shoots many flowers 
 
 [39] 
 
fail to open on some clusters, especially 
 those near the base and near the tip of 
 the shoot. Such clusters are short, and 
 small abortive flowers on them may make 
 them unattractive. If such a shoot is cut 
 back to a length containing six to eight 
 buds, any time between about August 25 
 and three or four weeks before the buds 
 open in spring, these flower buds will 
 open normally into clusters of full length, 
 longer than those toward the base of un- 
 pruned shoots and usually a little longer 
 than those on spurs. Even if the vine has 
 room to grow freely, a considerable 
 amount of pruning soon after the spring 
 bloom is advisable to cause rather strong 
 shoot growth and a longer blooming sea- 
 son in the following spring. Cutting these 
 shoots back to stubs with five or six buds, 
 in late summer, autumn, or winter, is 
 advisable to give better clusters. 
 
 The Chinese wistaria is often grafted 
 on Japanese wistaria roots, and many 
 sprouts are apt to grow from below the 
 union. They may grow more vigorously 
 than the Chinese wistaria and smother it. 
 An important part of good care is watch- 
 ing for these sprouts and pulling them 
 off while they are small. 
 
 What is said of the Chinese wistaria 
 applies also to the silky wistaria, W. 
 venusta, white or purple, except that the 
 white variety is considerably stronger- 
 growing than any variety of W . sinensis 
 and will require more pruning to keep 
 it to a given space. If left unpruned close 
 against the house, the trunk and roots 
 may become large enough to damage the 
 foundation, but it can easily be kept to a 
 safe size by pruning and will bloom as 
 well as if unpruned, or better. It is one 
 of the few best of white flowering vines. 
 
 Most varieties of Japanese wistarias, 
 W . floribunda, do not flower well in the 
 shade or after severe pruning and are 
 suitable only for situations where they 
 have full sun, or nearly so, and room to 
 grow freely, with little or no pruning. 
 They rarely produce any flowers in sum- 
 mer, after the spring bloom is gone. 
 
 Silky wistarias have some flower clus- 
 ters in much of the summer, besides the 
 spring blooming season, and Chinese wis- 
 tarias have many more. Rather severe 
 pruning soon after the spring bloom 
 seems to increase the amount of this sum- 
 mer bloom. Flowering in summer does 
 not reduce the number of buds for bloom- 
 ing in the following spring, but instead 
 increases it. Each summer cluster termi- 
 nates a new spur with four or five or more 
 leaves with buds in their axils that pro- 
 duce flower clusters in the following 
 spring. 
 
 Fig. 30. A vine of the magenta-flowered va- 
 riety of Bougainvillea glabra trained on a stake 
 until its trunk has become strong. Its heavy 
 flowering does not show in this picture. 
 
 [40 
 
Bougainvilleas. Highly unlike wis- 
 tarias in their blooming habits and in 
 resistance to cold, bougainvilleas are at 
 their best in the tropics. However, like 
 wistaria vines, a bougainvillea vine may 
 form a tangled brush pile on the house 
 if left unpruned, and like Chinese and 
 silky wistarias, the pruning to keep it in 
 the space available to it does not prevent 
 it from blooming, even if that space is 
 very much smaller than the vine would 
 naturally occupy. The earliest flowering 
 in summer may be on long succulent 
 shoots such as severe pruning causes. The 
 weakest shoots may be slow to bloom or 
 may never bloom. Branches containing 
 only such weak shoots, three to 12 inches 
 long, may well be cut off in the heavy, 
 early spring pruning. Strong shoots may 
 well be cut back to basal buds at that 
 time, so that the early summer growth 
 may nearly all be in fairly long shoots 
 that bloom well. The fact that the vines 
 seem to flower better, earlier in summer 
 at least, in dry, shallow soil, or in cans 
 with the roots cramped, seems out of har- 
 mony with this response to pruning and 
 is hard to explain. In coastal districts of 
 California all influences on time of 
 blooming are complicated by the strong 
 influence of temperature. A shoot in a 
 warmer position, owing to protection by 
 the house or some other object from the 
 cool ocean wind, will tend to begin bloom- 
 ing sooner than another shoot of equal 
 vigor that projects out into that wind. 
 
 As a flowering shoot elongates, flower 
 clusters are borne at each new leaf. Old, 
 branched, cluster stems remain after the 
 flowers have fallen. A long shoot that has 
 stopped blooming may have these con- 
 spicuous, bare stems at each leaf from 
 its tip back several feet. Shorter shoots 
 have fewer of these old stems at their 
 ends. The appearance of the vine is im- 
 proved if this part with the old flower 
 stems is cut from each conspicuous shoot 
 as soon as flowering ceases on it in sum- 
 
 mer. 
 
 On healthy bougainvillea vines, many 
 
 thorny succulent watersprouts may start 
 from parts of the branches or the trunk. 
 Unless they start late in summer they usu- 
 ally flower at the tips after they have be- 
 come six to 10 or 12 feet long. All such 
 shoots that are not needed to give the vine 
 a good form may well be pulled off as 
 soon as they are seen, most conveniently 
 when they are less than three feet long. 
 Those left may well have the tips pinched 
 out when they are three or four feet long 
 to cause them to form less rigid branches 
 that may soon begin to flower. Some of 
 them may be left to grow and flower nat- 
 urally if there is room for them, and espe- 
 cially if they are growing toward a 
 position where their flowers will show to 
 good advantage. 
 
 If the available space is not much more 
 than six to eight by 10 to 12 feet, vines 
 three or four years old may begin to need 
 a rather general pruning, shortening-in 
 of shoots or whole branches about mid- 
 summer, in addition to the thorough 
 spring pruning. Besides keeping them in 
 the space available, this may prevent 
 them from shedding nearly all their 
 leaves in early winter. 
 
 Bougainvillea shoots that get under 
 shingles or tiles swell even more than wis- 
 taria shoots and do more harm. Like the 
 wistaria, bougainvillea branches have 
 some rigidity and can be trained to inter- 
 esting forms or into special situations for 
 which vines without some rigidity of 
 branches cannot be used. Rather beauti- 
 ful effects can be produced by bougain- 
 villea vines trained on tall stakes (iron 
 pipes) to columnar, treelike forms, like 
 that in figure 30. 
 
 Chalicevine. The gold cup chalice- 
 vine, Solandra guttata, is even more rank 
 in growth than the bougainvillea, and all 
 its branches require support. Apparently 
 it can be kept down by pruning to a space 
 of about 10 by 20 feet without preventing 
 it from blooming, even when it is growing 
 in good soil; but several prunings each 
 year may be required. In fact, every few 
 weeks one or more shoots may become 
 
 [41] 
 
long enough to require cutting back to 
 keep them out of the way. Such summer 
 pruning causes growth of many succulent 
 branches. These set many flower buds, 
 especially in spring and autumn, but 
 much the largest percentage of them may 
 fall before they open. We cannot be cer- 
 tain whether or not this succulent condi- 
 tion caused by pruning increases the 
 number of expanding flower buds to fall. 
 Cool weather may be the dominant cause. 
 
 Honeysuckles. The giant honey- 
 suckle, Lonicera Hildebrandiana, has a 
 strong beauty when dying leaves and 
 branches are kept out. The long, fine 
 flowers seem to set as abundantly on long 
 shoots such as follow severe pruning as 
 on shorter ones, and so it can be a good 
 blooming vine when kept in small space 
 by pruning or when permitted to occupy 
 very large space. If it must be kept small, 
 a rather severe cutting out and cutting 
 back of branches in early spring may 
 have to be followed by repeated cutting 
 back of long shoots and pulling out of 
 young watersprouts during the summer. 
 
 The Japanese honeysuckle, Lonicera 
 japonica, can be used beautifully in care- 
 fully trained traces on the house wall or 
 in heavy masses on a fence or rock or 
 waste ground, but its branches have no 
 rigidity to give special character. 
 
 Trumpet Vines. Among these, the 
 Argentine trumpet vine (formerly known 
 and sold in California as Bignonia viola- 
 ceae, now classified as Clytostoma calliste- 
 gioides) is perhaps the best to give a 
 beautiful effect on a residence. It is more 
 resistant to cold than many other trumpet 
 vines, or than any other vine discussed 
 here except the wistarias, and seems cer- 
 tain to give an abundant spring and early 
 summer bloom. Heavy pruning does not 
 
 prevent this. Even if the whole vine is 
 cut back in spring to a long shoot, that 
 shoot with its branches may bloom heav- 
 ily a year later. On the other hand, the 
 stem and its branches are not short-lived. 
 A vine can be trained to a length of 30 
 feet or more with the branches long or 
 kept short, and it will live and bloom 
 heavily in spring and early summer for 
 many years. Its branches have less rigid- 
 ity than those of wistaria or bougain- 
 villea. Branches as long as two feet will 
 be pendant unless they are supported, but 
 on a vine trained along the side of a 
 building, shorter branches have strength 
 enough to hold rather large, conspicuous 
 clumps of dark lavender trumpet flowers 
 jutting outward and upward from the 
 stem of the vine. Rigidity of small 
 branches and the stiff, glossy, dark green 
 foliage give this vine more character 
 than the Japanese honeysuckle and other 
 limber vines. 
 
 The golden trumpet vine, Anemo- 
 paegma Chamberlayni (recently classi- 
 fied as a variety of the catsclaw Doxantha 
 unguiscati) , and its branches are more 
 limber. All parts must be supported. 
 Pruning to keep it in a small area does 
 not prevent it from producing an abun- 
 dance of its beautiful, canary-yellow 
 trumpet flowers. Pruning will usually be 
 the cutting away of some of its slender 
 branches with their waxy, bright green 
 leaves at near the ground level. 
 
 The blood trumpet vine, Phaedranthus 
 buccinatorius, does not seem to produce 
 many of its long blood red trumpet flow- 
 ers with yellow bases unless it is per- 
 mitted to grow rather freely and occupy 
 larger space than may be available at 
 small homes. 
 
 [42 
 
VARIETY INDEX 
 
 This index lists all plant varieties discussed in the foregoing pages. If you have a 
 pruning problem for a variety not listed here, see the Table of Contents on the outside 
 back cover. 
 
 Abelia, glossy, 34, 35 
 Acacia, 21 
 
 Sydney, 20-21 
 Arborvitae, 8, 30 
 
 Thuja occidentalism 30 
 
 T. orientalis, 30 
 
 var. Beverly Hills, 31 
 Ash, 12-13 
 
 Arizona, 12, 28 
 Avocado, 7 
 
 Brazilian glory bush, 37 
 Bougainvillea, 40, 41, 42 
 
 B. glabra, 40 
 Camphor, 13, 16-18 
 Carob, 15, 17-20, 22 
 Ceanothus (wild lilac) , 35, 38 
 
 C. impressus, 35 
 
 C. thyrsiflorus (blueblossom), 35 
 Cedar, 8 
 
 incense, 25, 32 
 
 deodar, 24-26 
 Chalicevine, gold cup, 41 
 Cherry, flowering, 28 
 Cotoneaster, 10, 34, 36, 38 
 Crape myrtle, 9, 33 
 Cypress, 8 
 
 false, 8, 30 
 
 Italian, 31 
 Elm, Chinese (evergreen) , 19-20 
 Escallonia, 34, 38 
 
 E. floribunda, 34 
 
 E. montevidensis, 34 
 
 E. organensis, 34 
 
 red, 34, 35 
 Eucalyptus, 20, 22-23 
 
 E. robusta (swamp mahogany) , 27 
 
 lemon, 22, 23 
 
 Mulga ironbark, 22 
 
 scarlet, 22 
 Eugenia, Australian brush cherry, 
 
 29,33 
 False cypress, 8, 29 
 Fig, rusty, 14 
 
 Firethorn — see Pyracantha 
 Hibiscus, 9 
 
 Chinese, 37 
 
 Honeysuckle, 42 
 
 giant, 42 
 
 Japanese, 42 
 Jacaranda, 28 
 Jasmine, Italian, 38 
 Juniper, 8 
 
 Live oak, California, 16-18 
 Magnolia, 14 
 Melaleuca, 22 
 
 M. genistifolia, 22 
 
 M. leucadendron, 22 
 
 M. styphelioides, 22 
 Mock orange, 33 
 Oleander, 33 
 Orange, 7 
 Pine, 8, 24 
 
 Bishop, 8, 9 
 
 Italian stone, 24 
 Pittosporum, 20 
 
 orangeberry, 20 
 
 P. undulatum, 36 
 
 Tobira, 20, 36 
 Plane tree, 13 
 Plum, flowering, 28 
 Podocarpus macrophylla, 32 
 Poinsettia, 37 
 Primus blireana, 28 
 Pyracantha, 36, 38 
 Rusty fig, 14, 15 
 Swamp mahogany, 27 
 Syringa — see Mock orange 
 Tea, Victoria, 5, 22, 35 
 
 var. Compact, 22 
 Trumpet vine, 42 
 
 Argentine, 42 
 
 blood, 42 
 
 golden, 42 
 Viburnum, Japanese, 37 
 Wistaria, 39-40, 41, 42 
 
 Chinese, 39-40 
 
 Japanese, 40 
 
 silky, 40 
 Yew, 8 
 
 English, 32 
 
 Irish, 32 
 
 Japanese, 32 
 
 [43] 
 
CONTENTS 
 
 PAGE 
 
 Pruning and Plant Processes 4 
 
 How plants get food for growth 4 
 
 Pruning and old buds 5 
 
 Pruning deciduous trees, shrubs, and vines 6 
 
 Pruning broadleaved evergreen trees, shrubs, and vines 7 
 
 Pruning conifers 8 
 
 Pruning and cold resistance 9 
 
 Choosing times to prune 9 
 
 Pruning Methods: Cutting to Stubs or to Laterals 10 
 
 Training Young Trees 12 
 
 Deciduous trees 12 
 
 Broadleaved evergreens 13 
 
 Large conifers .24 
 
 Pruning to Control Size 26 
 
 Cutting old branches 26 
 
 Preventing full growth 27 
 
 Pruning down for better flowering 28 
 
 Pruning Columnar Trees 29 
 
 Pruning Ornamental Shrubs 33 
 
 Keeping shrubs looking unpruned 35 
 
 Time to prune shrubs 37 
 
 Pruning Ornamental Vines 38 
 
 Variety Index 43 
 
 Co-operative Extension work in Agriculture and Home Economics, College of Agriculture, University of California, and United States Department of Agriculture co- 
 operating. Distributed in furtherance of the Acts of Congress of May 8, and June 30, 1914. J. Earl Coke, Director, California Agricultural Extension Service. 
 
 30m-3,'52(8045)JB