|If you work for any length of time at all with bonsai, you must understand and be comfortable with the process of ‘wiring’ your tree. Wire is used in bonsai for a number of reasons– none of which directly harm, stunt, or restrict the tree’s growth, contrary to some opinions outside the bonsai community.
Simply put, wire is applied to the trunk and branches of a tree in order to hold the desired shape of the tree’s design. Wire is an almost constant companion to a bonsai throughout its formative years and into its old age. It’s the rare bonsai, in fact, that does not sport at least a little wire on it for most of its life. It is a constant program of gently coaxing the branches into the desired planes. Young trees are full of vigor and will inevitably raise their branches as this vigor shows itself in juvenile growth habits. The branches must be brought down in a convincing imitation of a much older tree. Wire is used to separate and flatten foliage planes, spreading them out laterally, allowing sunlight and air to reach the inner branches, and displaying that very convincing characteristic of an older tree– bare inner branches and clearly visible branch junctions.
Traditionally the wire of choice is fire-annealed copper wire. Annealing the wire produces a unique but quite useful characteristic: The wire is soft and malleable when being applied, however the flexing and bending the wire experiences during the application creates ‘heat’, and the crystalline structure of the metal is realigned, making it quite firm and rigid after it is bent to shape. This is perfect for bonsai enthusiasts, because it means there is real strength to the wire and it will hold the shape you create.
Another type of wire found in bonsai is aluminum wire. Aluminum wire is very soft and malleable. It is much easier to apply but will not hold the shape as readily as copper wire. However, ease of production and availability have made it a very popular choice. Most aluminum bonsai wire is anodized to look like copper wire. Generally speaking one must use a heavier gauge (thicker diameter) aluminum wire to achieve the results of a thinner gauged copper wire.
How tightly should you wrap the wire around the trunk and branches? Tightly, but not too tightly. The idea is to set the branch firmly in position, not to constrict it. Since Time is a tool used by bonsai enthusiasts, we must look forward in time and see that by wrapping the branches too tightly, as the tree grows, the wood beneath the wire swells, increasing in diameter. In short order the wire will bury itself in the bark, ruining the design and greatly harming both the health and beauty of the tree. So, we wire just a little loosely to allow for branch growth, and to allow for more time to pass between wirings. No sense fully wiring your bonsai, only to have to cut it all off two weeks later as the tree enjoys a big spring growth spurt!
This brings up a good point– when is the best time to wire your tree? Usually it is when the tree is at its slowest growth phase– autumn through winter. For tropical and semi-tropical trees, this rule too applies, but even more so. Tropical trees can be rampant growers, and can outgrow a wiring in as little as ten days’ time. Many tropical bonsai enthusiasts find that using as little wire as possible makes for a more healthy bonsai. In my next article I will discuss an alternative to wiring, known as the ‘clip-and-grow’ method.