Growing bonsaix

Growing Bonsai
Publication Information
Information in this file was originally published under the title Growing Bonsai by the United States Department of
Agriculture, Home and Garden Bulletin No. 206, issued August 1973 by the Superintendent of Documents, U.S.
Government Printing Office, Washington D.C. 20402, Stock No. 0100-02772.
The publication was originally prepared by Henry M. Cathey of the Plant Genetics and Germplasm Institute at
Northeastern Region agricultural Research Service.
This pdf version was edited and compiled by C. Scott Clark, technical writer and web page designer. Other than
minor stylistic changes in text, no other changes were made in content, except for the substitution of color photo-
graphs, which replace the original black and white illustrations. Captions were changed as needed. Most photo-
graphs (Figures 1-13) were taken by Peter Voynovich and were originally shown in Outstanding American Bonsai
by Randy Clark, published in 1989 by Timber Press, Portland, OR. Figure 14 was photographed by Saxon Holt,
published in 1994 in Bonsai: an Illustrated Guide to an Ancient Art by Sunset Publishing Corporation, Menlo Park,
CA.
This document was last updated on April 6, 1999. This information is also located at http://www.peak.org/~cscottc/
bonsai-site/Growing_Bonsai.htm. Please send comments or questions to cscottc@peak.org.
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Contents
Introduction 3
Principles of Bonsai 3
Choosing a Style 4
Basic Styles 4
Formal Upright 5
Informal Upright 5
Slanting 6
Cascade 7
Semi-Cascade 7
Plant Selection Guide 8
Trees and Shrubs 8
House Plants 9
Obtaining Plants 10
Collecting Plants from the Wild 10
Importing Mature Plants 11
Nursery Plants 11
Shaping Bonsai 12
Overall Design 12
Pruning 13
Nipping 13
Wiring 14
Containers for Bonsai 14
Training Pots 14
Choosing Pots 15
Potting 15
Repotting 16
Growth Media 16
Seasonal Care 17
Spring Care 17
Summer Care 17
Fall Care 17
Winter Care 17
Coldframes 17
Watering 18
Fertilizer 18
Propagating Bonsai 18
Seedlings 18
Cuttings 18
Layering 19
Grafting 19
Displaying Bonsai 19
Indoor Display 19
Bonsai in the Garden 20
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Introduction
Bonsai are miniature trees grown in pots. The aim of bonsai culture is to develop a tiny tree that has all the
elements of a large tree growing in a natural setting. This look is achieved, principally, by branch and root
pruning and shaping, but other factors are also important. The texture of the trunk, its look of age, the moss
and the under plantings in the container — all contribute to the illusion of a miniature tree as it is seen in
nature.
A presentable bonsai can be created in a few seasons. Cultivating these miniature potted trees is both an
intriguing hobby, and a means of adapting a wide range of plants to specialized and decorative uses. Bonsai
require daily watering during their growing season, and, because the plants are rooted in shallow pots,
careful pruning.
Bonsai are kept outdoors most of the year, but — from time to time — these miniaturized versions of nature
are brought indoors for display. Only certain tropical trees, shrubs, and vines can be continually kept in-
doors full time as bonsai.
Bonsai, as an art form, stems from ancient oriental culture. It originated in China and was developed by the
Japanese. In the 13th century, the Japanese collected and potted wild trees that had been dwarfed by nature.
These naturally formed miniatures were the first bonsai.
When demand for the small trees outstripped the supply, Japanese gardeners began to train bonsai from
native trees. They shaped the trees to give them the illusion of age and naturalness. Over the years, the
Japanese devised standards of shape and form, which gradually began the classic bonsai styles.
American bonsai are much freer in concept and style than Japanese bonsai. American bonsai growers
have recognized that the horticultural and aesthetic rules are important, but are specifically aimed at
Japanese culture. Because of this, Americans have taken oriental styles and applied them to plants never
grown by the Japanese. Therefore, the rigid procedures and names used by the Japanese are not used in
this bulletin.
Principles of Bonsai
Not all plants are equally effective as bonsai. To produce a realistic illusion of a mature tree, look for plants
with the following characteristics:
· Small leaves or needles.
· Short internodes, or distances between leaves.
· Attractive bark or roots.
· Branching characteristics for good twig forms.
All parts of the ideal bonsai — trunk, branches, twigs, leaves, flowers, fruits, buds, roots — should be in
perfect scale with the size of the tree. Plants used for bonsai should have small leaves, or leaves that
become small under bonsai culture. Plants with overly large leaves, such as the avocado, will look out of
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proportion if chosen for bonsai. Sycamores also develop leaves that are too large. Certain species of both
maple and oak trees usually respond well to bonsai culture and develop leaves that are in proportion.
Among the plants with small leaves and needles are spruce, pine, zelkova, pomegranate, and certain oaks
and maples.
Plants chosen for bonsai should have attractive bark, and the trunk must give the illusion of maturity. The
trunk should have girth, but must remain in proportion to the entire tree. The trunk should taper gradually
toward the top of the tree. Sometimes one or two of the main branches must be shortened to emphasize the
vertical line of the trunk and give the trunk a balanced appearance.
To give the appearance of age, the upper one-third of the root structure of a mature bonsai is often exposed.
This is especially effective if the roots have good girth and form. Twisted and tangled roots should be
straightened before potting or repotting a tree to achieve an aged appearance. Bonsai from nursery stock,
and trees collected from the wild, should have a root system that will — when exposed — add to the
appearance of the finished bonsai.
Plants have a “best profile” just as people do. Decide on the front of the tree at the very beginning, because
planting and shaping are done with the front of the tree in mind. However, you may change your ideas
about the plants ultimate shape as you clip and prune.
The front of the bonsai should offer a good view of the main trunk, which must be clearly visible from the
base to the first branch, typically about one-third the way up. Everywhere on the tree, but mostly from the
front, the branches should look balanced and appear to be floating in space; they should not appear lop-
sided or top-heavy. The branches should not be opposite one another with their lines cutting horizontally
across the trunk. The branches give the bonsai the dimension and establish the tree’s basic form.
A bonsai should have a harmonious arrangement of branches without unsightly gaps. Flaws can be spotted
by looking down on a bonsai. Upper branches should not overshadow lower branches.
Before deciding on the shape of your bonsai, study the tree carefully, and take into account the natural form
of the species. Observe the way mature trees of the same kind grow in their natural setting to achieve an
impression of age and reality.
Decide on the final shape and size of your bonsai before starting. Make a rough sketch of what you wish to
create and use it as a guide.
Choosing a Style
Basic Styles
Bonsai can be classified into five basic styles: formal upright, informal upright, slanting, cascade, and
semi-cascade. These classifications are based on the overall shape of the tree and how much the trunk
slants away from an imaginary vertical axis.
The numerous Japanese bonsai styles are principally variations of these five basic styles. The styles given
in this bulletin apply to trees with single trunks. The single trunk style is the basic design that is simplest to
shape because the one trunk determines the overall composition.
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Formal Upright
The formal upright style has classic proportions and is the
basis of all bonsai. It is the easiest for a beginner to develop
because it requires the least experimentation, avoids the prob-
lem of selective pruning, and should almost immediately
become a displayable bonsai.
In this style, the form is conical or sometimes rounded and
the tree has an erect leader and horizontal branches. One of
the branches is lower and extends a little farther from the
trunk than the others (Figure 1). Also, the lowest two branches
are trained to come forward on the front side of the tree, one Figure 1. Note the off-center placement of this
slightly higher than the other. The third branch of this style redwood (Sequoia sempervirens) in its oval con-
extends out in the back of the tree at a level between the two tainer. This tree was trained in the formal upright
style, which is considered the easiest for the nov-
side branches to give the plant depth (Figure 2).
ice bonsai grower.
Plants in the formal upright style look best in oval or rectan-
gular containers. Do not center the plant when placing it in
the container. Plant it about a third of the distance from one
end.
In choosing a nursery plant for this style, make sure the trunk
rises from the ground in a fairly straight line. The trunk should
be straight and not fork or branch out for the total height of
the tree. Trim off the small branches or twigs that are too
close to the base and near the main stem. These branches
detract from the overall composition.
Informal Upright
Figure 2. The formal upright style features a
The informal upright style has much the same branch arrange- straight trunk, and a bottom branch that is lower
ment as the formal upright style, but the top — instead of and extends further from the trunk than its oppo-
being erect as in the formal upright style — bends slightly to site. This specimen is a Mugho pine (Pinus mugo
the front. This bend makes the tree’s branches appear to be ‘Mugo’).
in motion and enhances the look of informality (Figures 3
and 4).
The informal upright style looks best in an oval or rectangular container. It should be planted, not in the
center of the container, but a third of the distance form one end.
Many nursery trees are naturally slanted. This makes them well suited to the informal upright style. Check
the tree’s slant by looking down at the trunk from above — from this angle the top should slant to the front.
If this view is not attractive, you may move the root ball to slant the tree in another direction.
If you choose a vertical tree at the nursery, and want to train it in the informal upright style, simply tilt the
plant when potting it. When you do this, trim the branches and foliage so they are scaled to the size of the
tree.
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Figure 3. This trident maple (Acer buergerianum) Figure 4. The trunk in the informal upright style
bonsai, is trained in the informal upright style. bends slightly to the front. This specimen is 32
The style is similar in branch placement to the years old, a San Jose juniper (Juniperus san jose)
formal upright style, but differs because of the in training since it was a seedling.
angularity of the trunk.
Slanting
In the slanting style, the trunk has a more acute angle than in the previous styles. The lowest branch should
spread in the direction opposite to that in which the tree slants. The top of the tree is bent slightly toward the
front (Figures 5 and 6). The lower branches are arranged in groups of three, starting about one-third the way
up the trunk.
Slanting trees in nature are called “leaners” — trees that have been forced by the wind and gravity into
nonvertical growth. The attitude of the slanting style falls between the upright and cascade styles. This
style looks best planted in the center of a round or square container.
Figure 5. This common juniper (Juniperus com-
munis) , estimated to be about 80 years old, was Figure 6. In the slanting style the trunk has a more
collected in 1979, and has been trained in the acute angle than in the informal upright style. This
slanting style of bonsai. In this style, the lowest specimen is a Lantana, salvaged from a construc-
branch spreads in the opposite direction to the tion sight in 1959.
slant of the tree.
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Cascade
In the cascade style the trunk starts by growing upward from the soil, then turns downward abruptly, and
reaches a point below the bottom edge of the container. For this reason, the container should be placed on
the edge of the table, or on a small stand (Figures 7 and 8).
The cascade style has
most of its foliage
below the soil sur-
face. This style is
representative of a
natural tree that is
growing down the
face of an embank-
ment.
Training a tree in the
cascade style takes
longer than in the
slanting style. Figure 7. Elephant bush (Portulacaria
Figure 8. The cascade style of bonsai rep-
Choose a low-grow- afra), trained in the cascade style, has a resents a natural tree growing down the face
ing species instead of characteristic leader, which descends below of an embankment. This specimen is a three
forcing a tree that the bottom edge of the container. A cas- leaf Akebia (Akebia trifoliate) estimated to
caded bonsai usually looks best in a round be about 30 years old.
normally grows up-
or hexagonal container.
right into an unnatu-
ral form. Bend the whole tree forward so one back branch is vertical and the side branches fall naturally.
A cascaded planting usually looks best in a round or hexagonal container that is higher than it is wide. The
tree should be planted off-center from the cascading side.
Semi-Cascade
The semi-cascade style has a trunk that is allowed to grow straight for a certain distance, and then is
cascaded down at a less abrupt angle than in the cascade style (Figures 9 and 10). The cascading branches
are thought of as the front of the tree, and the back branches are trained closer to the trunk than in the other
styles. The semi-cascade should not reach below the bottom of the container, but should go below the level
of the soil surface.
Plants that are well adapted to the cascade and semi-cascade styles are prostrate junipers, and flowering
plants such as chrysanthemums, wisteria, willows, and star jasmine.
Before potting a tree for bonsai in any of the five styles, keep in mind the image of how the tree will stand
in the container. Don’t plant a tree one way, and then uproot it to make a change. Keep your overall theme
in mind when planting bonsai. Upright trees should have a stabilized look in the container; slanted and
cascaded styles often have their upper root surfaces exposed to imitate plants that grow this way in nature.
No matter what style you choose — whether single trunk specimens or groups of trees from single roots —
everything depends on your selection of plant material, and your ability to visualize the bonsai’s final form.
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Figure 9. This Shimpaku juniper (Juniperus Figure 10. The semi-cascade style has a curving
chinensis ‘Sargentii’ ‘Shimpaku’) in a hexago- trunk that does not reach the bottom of the con-
nal container was trained in the semi-cascade tainer as it does in the cascade style. This ex-
style. Prostrate junipers and flowering plants are ample is a little leaf Cotoneaster (Cotoneaster
well adapted to cascade and semi-cascade styles. microphylla).
Plant Selection Guide
Trees and Shrubs
The following alphabetical list of plants includes trees and shrubs suitable for traditional bonsai. This is not
intended to be a complete list. Specialty nurseries often have a wide selection of dwarf and semi-dwarf
varieties of many of these species. Dwarf plants, however, do not always convey the same impression as
their full size counterparts because the growth habit is quite different.
Apricot: Prunus species
Arborvitae: American, Thuja occidentalis; Oriental, Thuja orientalis
Azalea: Hiryu, Rhododendron obtusum; Indica azalea, Rhododendron indicum Kurume; hybrids
Beech: American, Fagus grandifolia; European, Fagus sylvatica
Birch: White, Betula alba
Boxwood: Buxus species
Burningbush: Euonymus nana
Cedar: Atlas, Cedrus atlantica; Deodara, Cedrus deodara
Cherry: Prunus species
Cotoneaster: Cotoneaster species
Crabapple: Malus species
Cryptomeria: Cryptomeria japonica and cultivars
Cypress: Bald, Taxodium distichum; Dwarf hinoki, Chamaecyparis obtusa var. compacta
Elm: American, Ulmus americana; Chinese, Ulmus parvifolia; Siberian, Ulmus pumila
Fir: Abies species
Firethorn: Pyracantha species
Ginkgo: Ginkgo biloba
Goldenrain: Koelreuteria paniculata
Gum: Sweet, Liquidambar styraciflua
Hawthorn: English, Crataegus oxycantha; Washington, Crataegus phaenopyrum
Heather: Calluna vulgaris
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Hemlock: Canadian, Tsuga canadensis and cultivars
Hornbeam: American, Carpinus caroliniana; Japanese, Carpinus japonica
Ivy: Hedera helix and cultivars
Jasmine: Winter, Jasminum nudiflorum
Juniper: Juniperus species and cultivars
Locust: Black, Robinia pseudoacacia
Maple: Amur, Acer ginnala; Hedge, Acer campestre; Trident, Acer buergerianum
Oak: English, Quercus robur; Pin, Quercus palustris; Scarlet, Quercus coccinea; White, Quercus
alba
Peach: Prunus species
Pine: Bristlecone, Pinus aristata; Japanese white, Pinus parviflora; Japanese black, Pinus
thunbergi; Mugo, Pinus mughus; Swiss stone, Pinus cembra; White, Pinus strobus
Plum: Prunus species
Pomegranate: Dwarf, Punica granatum nana
Quince: Japanese, Chaenomeles japonica
Snowbell: Japanese, Styrax japonica
Spruce: Picea species and cultivars
Willow: Weeping, Salix blanda
Wisteria: Japanese, Wisteria floribunda
Yew: Taxus species and cultivars
Zelkova: Graybark elm, Zelkova serrata
House Plants
American gardeners have taken bonsai concepts and have applied them to houseplants. By combining
traditional procedures for handling houseplants with bonsai concepts of design, growers have created dif-
ferent bonsai styles. The following alphabetical list consists of woody plants (native to the tropics and
subtropics of the world) that have been grown as indoor bonsai. These plants can be obtained from either
local or specialized nurseries.
Acacia: Acacia Baileyana
Aralia: Polyscias balfouriana, Polyscias fruticosa, Polyscias guilfoylei
Bird’s Eye Bush: Ochna multiflora
Camellia: Camellia japonica, Camellia sasanqua
Cape-Jasmine: Gardenia jasminoides radicans, Gardenia jasminoides
Citrus: Citrus species (calamondin, kumquat, lemon, lime, orange, and tangerine)
Cherry: Surinam, Eugenia uniflora
Cypress: Arizona, Cupressus arizonica; Monterey, Cupressus macrocarpa
Fig: Mistletoe, Ficus diversifolia
Herb: Elfin, Cuphea hyssopifolia
Hibiscus: Hibiscus rosa-sinensis Cooperi
Holly: Miniature, Malpighia coccigera
Jacaranda: Jacaranda acutifolia
Jade: Crassula species
Jasmine: Jasminum parkeri; Orange, Murraea exotica; Star, Trachelospermum jasminoides
Laurel: Indian, Ficus retusa
Myrtle: Classic, Myrtus communis
Oak: Cork, Quercus suber; Indoor, Nicodemia diversifolia; Silk, Grevillea robusta
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Orchid Tree: Bauhinia variegata
Oxera pulchella
Pepper Tree: California, Schinus molle
Pistachio: Chinese, Pistacia chinensis
Plum: Natal, Carissa grandiflora
Poinciana: Royal, Delonix regia
Pomegranate: Dwarf, Punica granatum nana
Powderpuff Tree: Calliandra surinamensis
Serissa foetida
Shower Tree: Cassia eremophila
You can also obtain books that supply information about growing plants indoors from your local library.
Obtaining Plants
There are many ways to obtain bonsai. At the beginning it is
best to work with the more common plants. Most are obtain-
able at local nurseries. Plants that are native to the area where
you live often make fine subjects for bonsai. But make sure
these plants meet the bonsai requirements of size, leaf, trunk,
and scale (Figure 11).
Some old favorites grown as bonsai because of their classical
good looks are Sargent juniper (Juniperus chinensis Sargentii);
Japanese black pine (Pinus thunbergii); wisteria (Wisteria flo-
ribunda, Wisteria sinensis); flowering cherries (Prunus Figure 11. A group planting in any of the bonsai
subhirtella, Prunus yedoensis); and gray bark elm (Zelkova styles makes use of only one species of tree. A
Banyan (Ficus neriifolia ‘Regularis’) is shown
serrata).
here.
Among the plants recommended for the beginner are:
· Firethorn (Pyracantha coccinea or Pyracantha fortuneana), which is an evergreen with small
leaves;
· Cotoneaster (Cotoneaster dammeri), which has characteristics similar to those of firethorn;
· Dwarf pomegranate (Punica granatum nana), which is deciduous, and has tiny green leaves; and
· Juniper (Juniperus scopulorum or Juniperus virginiana), which is a hardy evergreen with heavy
foliage that takes well to pruning.
In addition to nursery stock, plants for bonsai can be collected from the wild or propagated from plants in
your garden (See discussion of propagation). Growers can now purchase mature bonsai created in this
country; these plants have recently become available at selected nurseries. Mature bonsai plants also can be
imported from Japan, but only deciduous varieties ship well.
Collecting Plants from the Wild
The job of finding plants in the wild that adapt well to bonsai is difficult for the beginner. Traveling in wild
terrain where such specimens are found can be hazardous. Also, at least a year must pass before a plant
collected this way can be containerized, and much care is necessary to insure survival during this period.
Wild plants, however, often look older than they actually are and make handsome specimens.
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The best time for collecting plants in the wild is during March and April, when new growth or leaves have
not yet begun to sprout. Here, the collector must recognize when the wild plant is in its dormant period.
On a collecting trip the following items will be helpful: a small collapsible shovel; polyethylene sheeting
and string for wrapping rootballs; sphagnum moss for packing around the rootball; a container of water for
wetting leaves and rootball; and a small crowbar forgetting roots out of rocks.
Remember the following points when taking plants from the wild:
1. Get permission to dig from the owner of the property.
2. Do not randomly dig wild plants. Make sure that the plant you are removing is not on your State
conservation list. Remember that nothing can be removed from national parks and similarly con-
served areas.
3. When digging the plant you want, try not to injure the taproots. Get as much soil around the roots as
possible. Older trees will require greater care and a slower training schedule.
4. After you cover the roots and soil with wet sphagnum, wrap the rootball in polyethylene film. Wet
the branches with water frequently.
5. At home, unwrap the rootball carefully. (It is not necessary to unwrap the rootball if it is wrapped in
burlap.) Plant the tree in loose garden soil in a location that is protected from the sun and wind.
6. Water, and examine the roots of the new plant for several months. Feed the plant sparingly.
7. After at least 1 year, the plant can be dug up and placed in a container. (Large trees may have to go
into a succession of smaller containers before they are ready.) Trim the roots around the base care-
fully so the plant will fit into its container.
8. If shaping is necessary when potting a collected tree, prune the branches lightly.
9. Two years after the plant has been collected from the wild, start it on a regular training program.
Importing Mature Plants
If you are going to import bonsai trees from Japan, it is best to do so during their dormant period. Such
plants are subject to severe fumigation before they are allowed to enter this country and thus are likely to be
harmed by fumigation.
To find out which trees can be imported, check with the Plant Protection and Quarantine Programs, Animal
and Plant Health Inspection Service, U.S. Department of Agriculture, Hyattsville, MD 20782.
Bonsai plants are now available that have been trained in the United States. These plants have the advan-
tage of being acclimated to various areas of the country.
Nursery Plants
The easiest and best method for the beginner to obtain bonsai is to buy nursery stock and develop his own.
These plants come in 1- and 5-gallon cans and their root systems have become adapted to cramped condi-
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tions. Buy only young, healthy plants when purchasing nursery stock. When searching for potential bonsai
among nursery stock, do the following:
· Look for plants that are well rooted and well branched. The plant must be able to withstand severe
initial pruning.
· Inspect the overall plant and then push back the foliage and examine the base from all sides. See if
the foliage is full enough to be shaped into an interesting bonsai. Check to see if branches are where
you will need them.
· Do not purchase a plant that cannot be easily transplanted to a pot.
Do not thin the root system excessively all at once when placing the plant in a smaller container. By
thinning the roots gradually and reducing the root system, safely and over a period of years, you will not
damage the plant. If you prune and shape first and neglect thinning the roots, some plants may die.
Shaping Bonsai
Overall Design
Strive for flowing form when shaping bonsai. Visualize the overall theme and try to get a three-dimen-
sional effect. Remember to select the front, back, and sides of your bonsai before pruning, and don’t forget
to examine the roots that will influence the growth of these areas.
For overall design, the “rule of thirds” is a simple concept to
use as a basis for obtaining a pleasing form for your bonsai.
The “rule of thirds” (Figure 12) assures you of getting the
proper division of space. In this aid to design, the total space
is divided into thirds both horizontally and vertically.
Use your pruning shears judiciously to make changes that ben-
efit your bonsai. Fine adjustments are made by wiring, bend-
ing, and thinning (removal of branches). Remember that a
badly designed bonsai will not grow well.
Before shaping a plant into a bonsai, decide whether the best
attitude of the tree is upright, slanted, cascaded, or semi-cas-
caded. Examine the general form of the tree and note whether
it is straight or twisted. Match the potential of a tree to the
style that fits it best. Decide whether the base will rise from Figure 12. The “rule of thirds” is a useful design
the soil level or whether you will expose bare roots. aid when planning the overall form of your bon-
sai. The total space of plant and container is di-
Three basic operations are necessary to establish the basic form
vided into thirds, both horizontally and vertically.
in bonsai culture: pruning, nipping, and wiring.
You will need the following basic tools: a pair of sharp hook-and-blade pruning shears; a garden trowel;
blunt sticks; a pair of sturdy wire cutters; copper wire of various lengths; and a sprinkling can. Also useful
are scissors for trimming leaves, tweezers for nipping, and brushes for cleaning topsoil.
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Pruning
Nursery plants are often overgrown and need much pruning to establish their best form. Through pruning,
you control growth and form by removing excess foliage and ugly limbs.
Some points to remember when pruning are:
· Make all cuts above a bud, a side branch or a main fork of the tree. Remove all buds except those
on the outside of the trunk to force the growth outward and upward.
· Leave stubs flush with the stem; long stubs serve as an entry for insects.
· Avoid cutting back so far that you weaken the main branches.
When pruning, keep branches growing toward an open space instead of toward each other or the trunk. Do
not shear bonsai as you would cut a hedge; shearing makes the plant look artificial.
After deciding on the foliage form for your bonsai, remove all crossed branches until the tree takes on the
form you selected.
If you want to slant a tree that has been growing in an upright position and insure that branches take a
natural shape, prune it in an upright attitude, and then tip it to where it should be and work on it that way.
Next, cut back new growth and thin out excess branches. When pruning an upright style, remove unneeded
side branches and leave the center ones that will fill out as they grow.
Space out your pruning schedule, even if the plant has heavy foliage. Plants must have a certain number of
leaves for photosynthesis.
Protect pruning scars when removing heavy wood from thick branches or the trunk. Cut the wood as close
to the trunk as possible, pare the stump flush, then scoop it out with a chisel, making a shallow wound that
will heal without looking unsightly. Treat these wounds with grafting compound and they will be unnotice-
able after healing. Several years must pass before the bark will grow over these cut surfaces and replace the
scar tissue.
Nipping
A tree usually requires one heavy pruning in its life to establish its basic form. After this initial pruning,
shaping is done by nipping. Nipping, or pinching back, is done to shape and develop the trunk and to
control the overall size of the plant. Nipping controls new growth before it becomes so dense that it must be
pruned.
A twiggy plant can be made more dense when it is nipped. When all terminal buds on a branch have been
pinched, several side shoots develop. In this way growth is stimulated. This will give the plant a bushier
appearance.
Nipping is done not only to shape a plant but also to develop more luxuriant foliage. As the new growth tips
show up, nip them with your fingers, twisting rather than pulling. Also nip off tiny spurs that appear on the
trunk or along heavy branches. These may develop into unsightly suckers that will leave scars when re-
moved. Do not overdo this removal; be careful not to damage the foliage you leave on the plant.
Page 13
After the top of a bonsai is pruned, trim the roots. Try to keep all fibrous roots and maintain a balance, if
possible, of one branch for one root. Remove any roots that were damaged in digging. Leave the surface
root system intact and make it appear as if the roots cling to the soil surface. Prune roots with sharp, sloping
cuts to avoid damaging them.
Wiring
The wiring and bending of branches that give bonsai its shape is unique to the art. Wiring is done after
pruning when the tree has been thinned to essential branches.
Copper wire is usually used for shaping bonsai because it is flexible. The sizes of copper wire that are best
for bonsai are 10, 12, 14, 16, and 18. (No. 8 wire is heavy and should be used only for the trunk.) Wire as
light as No. 16 should be used for very thin branches, and for tying rather than bending.
Wire evergreen trees only during their dormant period when the branches can be shaped without damaging
growth. Wire deciduous trees only during their growing season.
The day before you wire a plant do not water it; this will make the branches more flexible. Once a branch
has taken on its trained form, remove the wire, straighten out its twists, and flatten it with a mallet for reuse.
Wiring and shaping should begin at the lowest point of the tree, working upward. Do the following when
wiring:
· Anchor the end of the wire at the base of the tree before winding it.
· Push the end of the wire deep into the soil.
· Wire from the trunk to the main branch.
· Use a foam pad under the wire to prevent damaging the bark.
· Keep the turns about 1/4-inch apart and spiral upward at a 45-degree angle.
· Do not wire too tightl and do not damage the leaves or stems.
One length of wire can serve for two branches by anchoring the center of the wire at the trunk.
After wiring, the plant is shaped or bent by hand. The trunk and main branches are gradually bent in the
planned direction. Never try to straighten a branch that has been bent; this may split the bark.
Branches sometimes snap, even when carefully wired and bent. If the branch is not completely broken,
rejoin the broken ends, and wind some garden tape around the break. These fractures often heal quickly. If
a branch snaps off, prune back cleanly at the first side branch.
Wire should be kept on the plant for not more than 1 year. Remove the wire before the bark becomes
constricted; ridges will form if the wire is left on too long. When removing a wire, start at the outer most
end of the branches, and take care not to harm leaves, twigs, or bark.
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