Training Bonsai: Pruning and Bonsai Equipment
By definition, the perfect bonsai should have an aged-looking trunk and a vigorous growth of branches and leaves. The proportions of the tree should be similar to those of natural growing trees in the country or in forests but in miniature. Perfect results can only be obtained by continuous intervention. This will involve frequentof the branches, leaves and roots, along with wiring, which moulds the trunk and branches into various accepted styles of bonsai. This section tells you how to shape your bonsai.
Whatever the growing technique, the purpose of pruning is always to control the growth of the tree by managing the development of branches, leaves and later its fruits (by thinning out). This is why pruning is so important throughout the life of the bonsai.
As with fruit trees, we must distinguish between pruning to form the shape of the tree and on the other hand for its care and maintenance. Both need special equipment for the delicate operations involved.
A set of good scissors or clippers, both efficient and well designed, is essential to produce trees which conform to the aesthetics of bonsai.
Branches should be cut with a pair of strong cutters and sometimes (older branches, for instance), a pruning saw.
There are two types of scissors, those with strong, thick blades and large, broad handles and those with short blades and long, straight handles. The former are for cutting leaves and the latter for nipping buds.
The above are the general, all-purpose tools you should have for bonsai. As well as these you should have wiring tools.
Pruning for shape
To a large extent, the quality of a bonsai depends upon this. Pruning should be carried out very early on trees grown from seed or propagated vegetatively (from cuttings, grafting or). However, it can be done much later on a tree collected from the wild.
As a basic rule, always cut back one of two opposite branches on the trunk. In this way, you will produce a tree with alternate branches in keeping with bonsai tradition. Beyond this simple fundamental rule, pruning for bonsai formation is intended to shape the tree to the form you want. Be discriminating when removing branches, since a branch cut from the trunk will not grow again and you may be left with an assymetrical or badly-shaped tree. Any error in your judgement may be rectified by grafting on a replacement branch – but this is always a delicate operation and not guaranteed to succeed.
Although there are certain rules (such as systematic pinching out of the tips to obtain a well branched crown), this sort of pruning is generally a matter of common sense. It is obviously necessary to cut out suckers developing at the base of the trunk of a broom shaped tree, just as it is to cut back the leading shoot of a tree that you want to form a bushy shape, the skill being in selecting the right branch to take over as the new leader. Cuts should be clean, so the tree can heal quickly. This often means using a pair of cutters with slightly curved blades.
For slightly thicker branches, the small hole left in the trunk should be filled with grafting mastic to accelerate healing and eliminate all traces of the scar where the bark has grown back. Where a pruning saw has been used, it is almost always necessary to trim the cut with a pair of cutters or the blade of a grafting knife.
Tools should always be sharp and clean. Sterilize the blade with a flame after each pruning, to reduce the risk of transmitting viral diseases.
At this point, it might be useful to stress the quality of the tools you use. Traditional Japanese tools are certainly not cheap, but they are perfectly adapted to the requirements of bonsai cultivation. Do resist the temptation to use ordinary secateurs, or, for that matter, any other tools. You will only risk ruining your tree completely for the sake of a small outlay.