To form a bonsai exactly it must be wired. That means the branches are wrapped with bonsai wire of various thicknesses and bent into the desired position.
Almost more important than the correct wiring of a bonsai is the unwiring. Many mistakes can be made when unwiring a bonsai. These mistakes can quickly and significantly degrade the quality of a bonsai.
When should the bonsai wire be removed ?
- Once a branch holds the position without wire. This can be the case in some, quickly woody deciduous trees (spindle tree, azalea bonsai, privet bonsai) after a short time. Young shoots of the Spindle tree are often stable 6-8 weeks after wiring and need no more wire.
- When the bruise / contusion become too deep and then stay visible for a long time. Especially in trees with very smooth bark (Japanese maple bonsai) the case.
- If parts of the branch could die off due to the pressure of the wire.
- Often branches are wired at the end of the growing season. In many cases, consider removing the bonsai wire before budding. Without leaves, this is much easier. And during the stormy spring growth, the wire quickly grows in.
How is it done ?
Of course, after a bonsai has been wired it will continue to grow. That is also desired. Only then will new wood be formed, the wired branch will thicken and later on the new position can be held without the help of bonsai wire.
The thicker the branch becomes, the more the wire pushes in. It leaves clearly visible traces.
As long as the wire pushes into the bark only slightly, that's no problem. In most bonsai tree species (for example, larch bonsai, white pine bonsai), the pressure points quickly disappear after the wire was removed. Only in case of bonsai with a very smooth bark you must be careful when the wire pushes in to much. On smooth bark, traces of wire are visible for a very long time.
If a wire pushes harder (see picture below) then the time is ripe to remove it. For this a wire cutter for bonsai is used.
Due to the special construction of these wire cutters, the bark is not damaged during cutting - a great advantage over e.g. a side cutter from the hardware store.
In case of a pine tree these contusions are no longer visible in a year.
For many bonsai with very soft wood (such as most conifers), new wire often needs to be applied after unwireing. Otherwise the branch would soon take the old position again.
The wire should be applied against the previous direction. So the old pressure marks can disappear and the branch is held in the desired position without danger.
It is important to control a wired bonsai often to prevent ingrowth of the bonsai wire. By ingrowth the bonsai enthusiasts understands that the wire is pushed in so far that it can not be removed without injury. This should be avoided as much as possible.
A partly ingrown wire on a Scots pine is shown on the next pictures. The resulting deformations and wounds can be seen for a long time.
Ingrown bonsai wire is difficult to remove. It is best to cut it into small pieces and try to pull it out laterally through the wire channel.