One of the great differences between pen tsai and bonsai tree is the latter’s use of bonsai wiring as a common technique for changing the shape of the tree (pen tsai relies heavily on the clip and grow method, supplemented by hanging weights). Bonsai wiring can do a great deal to change the shape of the plant, but it can also do a great deal of damage to the plant if done incorrectly.

There are two kinds of bonsai wire commonly found in the hobby; copper and coated aluminum. Copper is usually something someone has made themselves (old electric cable they’ve stripped coiled and heated red hot to soften. It is much harder to bend than the aluminum but a smaller gauge is necessary to hold the same branch. Often the folks who do copper are reluctant to cut off the bonsai wire they have invested so much work in, but too many heart rending branches lost have sent me forever to cutting off my aluminum wire instead of trying to untwist a strand of copper I’d had a year too long anyway. The copper is a good fit because it doesn’t let you over force the branches as much as aluminum.

Bonsai Wiring should not be done to a plant, or left on through the peak growing season. Bonsai Wiring in fall or winter is best.

Apply by sticking the wire into the soil at the base of the trunk and winding it up the tree to the first branch at a 45° angle. Wire the length of the branch, always using your thumbs to press the length of the wire gently but firmly onto the trunk or branch (using the end of the wire as a handle and twisting it around the tree usually makes the wire too tight on the branch and can cut off circulation) If the wire is too loose there will be no holding power and the branch will return to its original position. Twist the wire around the end of the branch and remove the excess. Repeat for the back branch, then the right and so on through the branches that need wiring.

Six Tips for Wiring a Bonsai

  1. Always use both thumbs on either side of a bend to distribute the strain. Exercise extreme caution bending main branches, especially where it meets the trunk of your tree.
  2. When bending a branch up, wire from under the branch.
  3. When bending one down, come over and around the branch.
  4. Never leave a wired tree in full sun.
  5. Don’t expose a wired tree to extremes of temperature (bring it in on a really cold night).
  6. Remove the wire as soon as you see it starting to cut into the tree; remove it by cutting it off in small pieces as unwinding breaks branches.

For trees with softer bark, (serissas, cherries etc.) wrap the wire in raffia (usually available where you get wire) or paper tape so the wire won’t hurt the bark. As the conductive channels can be damaged in wiring, keep a close eye on wired trees, branch by branch so that you can unwire the appropriate branch at the first sign of trouble.

For bending thicker wood, lay another piece (or two) of wire along the trunk or branch to be bent and then coil your wire over that in the normal fashion. Enjoy.