Bonsai Wire

Bonsai Wire

To me bonsai wire is like a paintbrush and the bonsai is the canvas. After all, as bonsai enthusiasts we are practicing the art of bonsai. Wire is wrapped around the trunk and branches and allows us to manipulate and position them to “paint” the tree that we envision.
Without this wire, we would be limited in our designs or at least it would take a lot longer to get there. Before wire practitioners would hang rocks on a string to position branches and I doubt they could get the bends on the trees that bonsai wire allows us to do so easily.
You could use the clip and grow method if you wanted. That would take forever on some types of trees and probably never succeed to point that again wire allows us to.
That is why we use bonsai wire.

Aluminum Bonsai Wire

Copper Bonsai Wire

When to Wire?

You can literally wire a bonsai anytime of the year but there are a few things to think about when wiring.

It is easier to wrap the wire around a branch when there is no foliage on the tree. This is in the spring before the tree leafs out, in the summer after defoliation and in the fall after the leafs fall off. Why do we wrap the wire around a branch or trunk? To make bends and add movement to the tree. When we make bends we are damaging the cells in the branch and the tree becomes a bit weaker as the tree tries to heal.  This healing is what causes the branch to hold its shape.

Here is the catch.

  • In the springtime before the tree leafs out you have to be careful not to knock off buds. The tree also swells and grows fast during this time so you have to watch the wire so it does not cut into the branch or trunk and cause damage. This quick growth also means that the branch will most likely hold the bends quicker. Make sure there are no more frosts, or you will have to protect the tree.
  • In the summer after defoliating is a good time because you can see the structure of the tree and you don’t have to worry about leafs getting in the way. This gives enough time for the tree to heal before the first frost.
  • In the fall after leaf drop is not the best time to wire.  There is no time for the tree to heal itself and you will probably end up losing branches. With the proper aftercare you can still wire, but I would wait until spring or so.

Where to buy bonsai wire?

While you are here at Sumo Bonsai Supply you can check out our offerings of wire. In our inventory, we have aluminum wire from 1mm-6mm and copper wire from #6-#20. You can order it here. Bonsai Wire

Copper or Aluminum Wire?

Copper Wire:

  • Best choice for Conifers
  • Needs to be heat annealed copper
  • More control and strength than Aluminum wire

The copper wire needs to be heat annealed before being used on a bonsai. The regular copper wire is to hard to use and you would have a good chance of damaging the bark on the tree. Annealing the wire softens the wire and allows it to bend more easily.  Once annealed copper bonsai wire is bent it hardens. We call this work hardens. This “ability” is important. It allows you more control of your bends because the wire is soft, but as you make your bends the wire hardens and becomes a lot harder to move so the bend holds better.

Heat Annealing is different than electrical annealing and that is an important fact to share because the electrical annealed wire is not as soft as heat annealed.  Heat annealed copper bonsai wire is created by taking copper wire and heating it so it is uniformly red hot, then quickly dunking the wire in cold water to cool it.

It is said that copper wire is best for coniferous trees. Why? Conifers grow more slowly than deciduous trees and the wire needs to stay on the tree for a longer time. Copper won’t rust like the aluminum wire. A lot of conifers are very flexible and the softness of copper followed up with the work hardening “ability” creates a strong hold on the bends.

Aluminum Wire:

  • Best choice for Deciduous species
  • Uniform strength
  • Easier to bend and manipulate. Better control

Anodized aluminum bonsai wire is easier to bend and manipulate than copper wire but unlike copper, aluminum does not harden as it bends so you will need to use a little thicker wire than with copper to hold some bends.

If copper is not annealed properly it can end up pitted and have spots that are stiffer or weaker than others. Aluminum, on the other hand, has uniform consistency and is predictable.

Deciduous trees tend to grow quickly so wire needs to be removed sooner than on coniferous trees. Aluminum wire works well for deciduous trees because you are not going to be making drastic bends on a deciduous tree, so you won’t need the strong holding power of copper. Aluminum wire will discolor, rust and become unsightly on a tree once exposed to the elements. With deciduous trees growing quick you will have to watch every week to every couple days for the wire to start biting into the bark. As soon as it does you will want to remove it and reapply wire. This reason alone tells me to use aluminum wire. Copper prices keep going up making the copper wire more expensive.

This is the first year that I have used copper wire and I have to say that I love it. General thinking and reading tell me to use Copper wire on Conifers and aluminum on Deciduous trees. I will be following this from now on.

How to Wire

There are many good sources out there from people who know how to like pros because they are pros.  I will share the links for you.


Good Views

This is another video series on bonsai wiring.  This one is by Colin Lewis and is hosted on  Its free, but you will have to signup with

Wiring Course by Colin Lewis

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