The Basics of Bonsai Wire

Chances are, if you’ve spent any amount of time browsing through bonsai photos online, or visiting a local bonsai exhibition, you’ve seen a bonsai wrapped in bonsai wire. Among those who regularly work with bonsai, wire is commonplace. For those uninitiated to the practice of using wire to manipulate the shape of a tree, the sight of a wired bonsai can be confusing.

I recently had a neighbor visit, and when he saw a few junipers that had been wired and re-shaped he asked “why do you wire bonsai?”

In this article, we’ll explore the basics of bonsai wire.

Basics of Bonsai Wire

Why Do We Wire Bonsai Trees?

To understand why we wire bonsai, it is important to understand what bonsai is.

We could spend an entire book answering that question, but for this article, let’s imagine that a bonsai is a stylized, miniature representation of a full grown, mature tree.

To achieve that miniaturized look, young trees (or bushes, in some cases) need to be manipulated, pruned, and shaped to become a reflection … a smaller reflection, of their larger counterparts.

MASB 2018

But, why is wire needed to accomplish this transformation? Because young trees and old trees grow differently.

Think of a young tree. It will typically have branches that grow outward, or more commonly, upward. Now think of a mature tree in the wild. Mature trees have branches that grow downward, rather than upward.

So we use wire to change the directionality of the branch … to pull them downward … to imitate a mature tree.

Types of Bonsai Wire

While it’s true that you could realistically use any type of wire to shape your tree, in general, bonsai enthusiasts use two types of wire when styling their trees:

  • annealed copper (used normally on conifers)
  • anodized aluminum (used normally on deciduous)

Annealed Copper Bonsai Wire

Annealed copper wire is copper that has been annealed (heated in a fire) to make it softer and less brittle, thus easier to work with. Once annealed copper has been bent and twisted around a branch, it becomes more rigid.

Annealed Copper Bonsai Wire

Copper wire is used for strength. This strength prevents a branch (or trunk) from springing back into its original position once wired.

There are a surprisingly few numbers online retailers who sell annealed copper wire. However, Adam’s Bonsai carries a nice selection.

Anodized Aluminum

Anodized aluminum wire is aluminum that has been anodized (electrochemical process that changes the surface of the wire, protecting it against corrosion). It comes colored in a dark colors like brown and black.

Aluminum wire is great for beginners because:

  • it’s less expensive than copper
  • it’s softer to work with than copper
  • it’s more readily available than copper

Anodized aluminum wire can be purchased online.

Wire Sizes

Bonsai wire comes in many different sizes … from the thinnest diameters, ideal for shaping tender foliage on a branch, to the thickest diameters, made for heavy jobs, like bending large branches.

Bonsai Wire Uses

We’ve established that bonsai wire is used to shape a tree, but did you know it has other uses also?

Trunk Shaping

Often young trees are wired on their trunk to alter it’s shape.

Young trees often have a very straight truck. In the wild, very old trees often have a twisted or gnarled trunk. Using wire, we can mimic the shape of an old tree by adding movement with bends or twists.

Branch Shaping

As previously mentioned, wire is often used to re-arrange branches and pull them down, creating the look of an older tree. Wire is also used to “place” branches in the final design of a bonsai. This serves two purposes:

  • aesthetics – to create a beautiful tree
  • health – to allow light to penetrate the foliage on all the branches

Guy-Wire

Most typically, wire is wrapped around a branch, then the branch is moved into it’s final position and the wire holds it in place. However, in some situations, a different wiring technique is used to move a branch to the desired location … a guy-wire.

Bonsai Guy Wire

As you can see in the photo, these wires extend from a branch to an anchor (sometimes on the pot, or sometimes on the trunk).

Wiring the Tree to the Pot

You might not realize this, but bonsai trees are actually wired to the pot they live in. This part of the wiring process is invisible, because it happens below the surface of the soil.

Most bonsai pots have small holes in the bottom. These act as both drainage holes and anchor holes.

During a repot, a tree is held in place with two aluminum wires that criss-cross its root ball and are secured to the pot.

Securing Drainage Screens

Another invisible wiring application occurs underneath the pot.

Drainage holes require a plastic mesh screen to prevent soil from falling out of the pot. To secure the mesh screens (so they don’t move out of place), small pieces of aluminum wire are used.

Conclusion

As you can see, wire has many applications in bonsai. From securing the tree to the pot to shaping and styling, bonsai wire is a versatile tool in a bonsai artist’s toolbox.

If you’re just getting started in bonsai and you want to add shape to your tree, pick up a few rolls of anodized aluminum. The process of learning to wire a tree can be fun and rewarding.

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