Shaping Your Bonsai

Strive for flowing form when shaping bonsai. Visualize the overall theme and try to get a three-dimensional 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.

Formal Upright Mugho Pine
Fig. 12 -- The "Rule of Thirds" is
a useful design aid when planning the overall
form of your bonsai. The total space of plant
and container is divided into thirds, both
horizontally and vertically.

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" (see fig 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 benefit your bonsai. Fine adjustments are made by wiring and bending 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 semicascaded. 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 the soil level or whether you will expose bare roots.

Three basic operations are necessary to establish the basic form 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 top soil.


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: 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 unnoticeable after healing. Several years must pass before the bark will grow over these cut surfaces and replace the scar tissue.


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 removed. Do not overdo this removal; be careful not to damage the foliage you leave on the plant.

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.


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:
  1. 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.
  2. 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 tightly, 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 outermost end of the branches, and take care not to harm leaves, twigs, or bark.

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