Wiring is the practice of wrapping aluminum or copper wire around the bonsai trunk or branches to shape the tree. Training bonsai is never easy, but it can be made easier by proper preparation and execution. Here are some basic guidelines.
Pruning a bonsai is a selective process that helps determine the number and position of branches and leaves. But to affect the overall shape, wiring is needed. This practice is critical to achieving the balance and form needed to make the bonsai into a completed work of art.
By wrapping the trunk and branches with wire of the right length and thickness in the correct way, the basic bonsai style is created. No wrapping at all results in a formal upright (chokkan), for example, while to create the cascade (kengai) requires extensive wiring over many months or longer.
Since wiring puts stress along a trunk or branch, it’s essential to exercise extreme caution and patience during the process. The alternative can easily result in a cracked branch, or worse, a cracked trunk and a dead tree. Also, it’s possible to wrap too tightly or at the wrong season. The result will be scarring that can kill the tree or create damage taking months or years to heal.
Begin with a sketch or computer drawing capturing your vision of the final result. It doesn’t have to be final, but you should have an image in mind as your goal. Unless your goal is to only produce a small effect on one or two branches, start at the trunk, then move to larger branches, doing the smallest branches last.
Before wrapping the intended tree, practice. Start with a simple wooden pole or small ordinary tree branch, just to get the feel of the wire and develop the dexterity to hold the branch and wrap at the same time. Once you’re comfortable holding the branch with one hand and wrapping with the other, without bending or tugging anything but the wrapped part, you can move to the bonsai tree.
Selecting the proper month to begin can be complex. Different species begin and end their growing and dormant phases at slightly different dates. The amount of growth during a given month also varies by type of tree.
Some deciduous (leafy) trees are more delicate in the spring, when their growing season begins and sap begins to flow. Caution dictates waiting until later when the sap flow is lower. Summer is preferred.
Waiting too long, however will result in lost growing activity, which helps shape the result. Pine wired in autumn, by comparison, can easily experience scarring if the wire isn’t checked every couple of weeks.
Wiring in winter is possible, but because of low or no growth during this period will require extra time and patience.
Scarring occurs when wire is wrapped too tightly and/or left on too long and bark begins to grow around the wire. It can take years, sometimes forever, for scarring to heal. An ounce of prevention is worth ten tons of cure, in this case.
To minimize sap flow, wire when the tree has been slightly dried. Too dry and you risk cracking a branch. Too wet and sap flow creates branch pressure, also encouraging cracks.
Wiring, like every other bonsai practice is a delicate balance requiring learning, patience and practice.