Article written by Gary English and published on this website with kind permission of The Gardener magazine.
© Gary English gary@cybersmith.co.za
© The Gardener Magazine SA - Editor: Tanya Visser tanya@thegardener.co.za
Advanced Bending
Bonsai - Advanced wire techniques.
In the last issue I discussed the Clip and Grow or Lingnan technique. Although this was the principle method for shaping trees for many centuries, it was not the only method employed. Throughout the development of bonsai, a wide variety of methods were used to temporarily reposition already established branches. The basic principle is the same. If a branch is repositioned, and held firmly in place for long enough it will retain its position once the brace has been removed.
The time period that the brace must be left on for varies from species to species, depending normally on the speed of growth of that species, and also on how hard the wood is. The age of the tree and the thickness of the branch in question also has a bearing on the time factor, and only by practice and trial and error can a bonsai artist gain a feel for this. In most cases one growing season would be sufficient to achieve the desired result. Figs and Acacia are common examples of faster growing trees. Slower growing hardwood trees like Scotia and Carissa take a lot longer to retain their new shape and in cases like these one can leave the brace on for a couple of seasons.
Wrapping wire around a branch is the most common method, but as always it must be carried out with care. Wire can easily cut into the bark leaving unsightly scars which can take many years to disappear, and often never. Interestingly, some baobab trees in Botswana (I believe), still clearly carry the "signatures" carved into them by companions of the famous Dr Livingstone on one of his early expeditions. Also of interest is that the doctor himself declined the opportunity to deface the magnificent trees himself.
When wrapping wire, it is advisable to wrap the branch with wet raffia before wrapping the wire to provide some protection for the bark. Some junipers are unusual in that a small amount of wire cutting actually adds to the visual impact, but I don't advise novices to attempt this until they are more comfortable with that species of tree.
Another useful technique using wire is the hook method. A U shape is bent into one end of the wire and then hooked onto a branch. The other end is then secured firmly onto some convenient point, either another branch, a strong root or even the pot itself. An extension of this method is to close the two hooks so that the piece of wire looks like a long oval. Then place a sturdy stick through the middle of the oval and twist the oval clockwise or anti-clockwise. With every twist the length of the oval will become shorter, pulling the branch into position. The wire will eventually resemble a cable. This is a very secure method, and will hold the branch firmly which is essential. Again, it is very important to protect the bark or cambium from damage. I have seen a few good methods for this. Wrap a piece of stocking around the wire in the area where it presses against the bark to form a bandage. A second protective measure is to slide a piece of surgical tubing over the wire. Remember that the twisting cable will exert enormous pressure on the bending branch particularly if it is a fairly thick one. The best time to do extensive bending is early spring when the branches are growing quickly and are more flexible, but if done with caution bending can be done at almost any time of the year.
Some enterprising folk make special metal clamps to push or pull branches and even trunks, but one of the pitfalls of this is that unless the clamps are made of non-corrosive materials like stainless steel they tend to rust and stain both the clamp and the tree itself. Remember your tree will still be standing outside in the rain for 8 to 12 months or longer.
Another method employed, but less successfully in my opinion, is the practice of hanging weights from the end of a branch. There are a couple of drawbacks with this method but the main one is that the branch in question is seldom held in one position long enough for it to set in place.
All of the above mentioned wire techniques give trees a more graceful elegant appearance as opposed to the dramatic angles and taper achieved by the Clip and Grow approach. The decision to use either method or a combination of the two is purely up to the artist themselves, and is more often guided by the quality and shape of the original material than by a specific preference. In reality I have seen few trees that are pure Clip and Grow, and the same applies to pure wire work. Most material is a combination of both. The choice is yours.