The objective is to train the bonsai to grow in a required structure and style. Applying the wire correctly so that the tree is not damaged requires skill and experience in order to do it well. If a number of wires are needed to be applied to different parts of the tree, the level of complexity is considerable. The techniques that are required have been developed over centuries and to achieve them in practice is considerably rewarding. Some basic principles have still to be adhered to in order to avoid problems from an early stage.
Bonsai wire is normally made of aluminium or copper. Aluminium is usually considered to be best, though bonsai copper wire, being a little stronger, is sometimes used for the more springy branches such as those of young conifers. Ferrous wire is too stiff for normal use, can damage the bonsai tree and is also likely to rust.
Applying Bonsai Wire Correctly
Bonsai wire is wrapped around the part of the tree that it is intended to shape. This is usually a branch, but can also be a shoot or the trunk of a young tree. The age of the bonsai tree is a significant factor. An older tree will take much longer to set into a new position, while a young shoot can normally be set relatively easily. Damage should be avoided as it detracts from the final appearance, though in some forms of bonsai the stripping of bark is a deliberate practice in order to highlight the contrasting color of dead wood. Minor cracks in bark will normally repair itself and disappear as the tree ages, but is best avoided as much as possible.
Wiring bonsai too loosely to the tree will not generate enough strength to direct the growth of the tree, whilst wrapping too tightly will unduly restrict tree growth and could damage or even kill the part of the tree being wrapped. The optimum technique for most bonsai requirements is to wrap the coil of wire so that:
- the wire is in gentle contact with the bark of the tree
- the coils of wire are evenly spaced
- the coils all lie at an angle of forty-five degrees to the direction of the branch or tree part being wrapped.
Experience helps the practitioner assess which thickness of wire is appropriate to train the tree, while skill and practice help him or her to determine when the bonsai wire will need to be loosened off, removed or re-applied as the tree grows. As many bonsai trees will outlive their owner, the best care and attention during the early stages determine the lasting legacy that can be created by a good bonsai sculpture.