Mugo Pine branch with standard coiled wiring

The easiest and most common way to bend any branch into position is to coil it with aluminium or copper wire, manipulate it by hand and with the aid of the coiled wire, it then remains in its new position. (Wiring article)

In some situations, prior to applying the wire it is useful to protect the bark and the wood by using raffia (or similar) to stop the branch cracking or to stop the bark separating from the wood. (See Article)

However, with all tree species, there is a point where a branch is too thick to physically bend with just the strength of your fingers or there is a danger of the branch (the wood) snapping. For some tree species this can mean a branch as thick as 2.5cm/1" or more and for some species with brittle wood, as thin as just .5mm

Note: As applies with all wiring and branch-bending techniques, always be wary of snapping branches by bending them too far, too quickly! All branches of any given thickness have a certain amount of elasticity that allows them to be bent comfortably. After this point has been reached, a branch will snap, very possibly leading to the loss of the branch. The amount of elasticity in a branch varies greatly between tree species and knowing how far a branch can be bent is a skill that requires experience. If you are in any doubt as to how far a branch can be bent in one session, leave it to heal and then bend it further at a later date.

 

Guy Wires

Guy wire anchored to a thick root using a single strand of 1mm wire to bring down a Hawthorn branch.

The first technique worth covering in this article is the use of guy wires. Once the thick branch has been bent (either by hand or by using one of the techniques described in this article), it needs to be held into position until it sets. A piece of wire is attached from the newly bent branch to an anchoring point to create a guy wire. The guy wire simply stops the branch returning to its original position.

Various anchor points can be used; another branch on the tree, a jin, a hole through the side of the (training) pot, a thick surface root or even a small brass screw or hook, inserted into the trunk.

A guy wire made from copper wire is always preferred over aluminium for it's greater strength and lack of elasticity. Aluminium guy wires can begin to stretch over time, allowing the branch to move slightly out of position.

For aesthetic reasons, try to use the thinnest gauge wire possible. For most situations, 1mm copper wire is adequate though 1.5mm can be necessary when the guy wire requires extra strength.

Guy wires are an incredibly useful bonsai technique. However they do have limitations; guy wires have no control over the shape or movement of a branch and less control over it's precise position. The guy wire can only pull a branch in one direction whereas coiled wire allows much greater control and freedom of manipulation along the entire length of a branch. For this reason guy wires are generally limited to 'holding' branches into position and are used in addition to coiled wire techniques rather than replacing them.

 

The upper branch of this Acer palmatum has been notched and is held into position with a guy wire tourniquet. Electrical flex has been used to protect the bark.

If a guy wire is simply tied around the branch, it will quickly become embedded in the bark so some protection fis required. I use old electrical flex with the wire stripped out and the bonsai wire threaded through the casing. Rubber padding can be used but has a tendency to slip around as the guy wire is fitted to the branch.

Branches that have been bent using coiled wire techniques set into position more quickly than they will with guy wires. However as long as some cushioning is provided (as described above), guy wires do not cut into a branch as it grows and so can be left in position for a longer period of time. (For this reason guy wires are also very useful for pulling the branches of field growing trees into position without the risk of deep wire scars).

Guy Wire Tourniquet

A tourniquet can be created by creating a doubled-up length of copper wire (instead of a single strand of wire with normal guy wires), looped around the bent branch and it's anchoring point.

A guy wire looped over the bent branch and it's anchoring point ready to be twisted. (Note: For clarity, cushioning is not shown in the image, however, always provide protection for the bark from the wire)

As the name suggests, a metal bar is inserted in between the two lengths of wire which are then twisted together.

The advantage of using a guy wire tourniquet is that as the two lengths of wire are twisted together, they shorten and will pull the branches together with a great deal of strength. This is especially useful for moving very stubborn branches a few degrees further than might be possible by hand. Additionally, for brittle branches or branches where there is a risk of splitting or snapping, the tourniquet can be tightened slowly over a period of weeks, reducing the risk of damage.

The central leader of this Acer palmatum 'Kiyohime' has died back. To fill the gap in the foliage crown, it has been necessary to move some very thick and very brittle surrounding branches. This has been carried out over the course of a growing season with the use of several tourniquets that have been twisted at regular intervals.

Turnbuckles

Turnbuckles work by the same principle as tourniquets. However, rather than pulling the branch and anchor point closer together by twisting the guy wires, a turnbuckle is used to pull two guy wires together by tightening the buckle itself.

Turnbuckles are advantageous as (if long enough) they can move a branch further than the limited distance afforded by a tourniquet, however, they are more obtrusive and unpractical to use in tight spaces.

Branch Clamps (sometimes referred to as branch benders)

Branch Clamp

These things are still found for sale from various bonsai outlets and should be regarded as just a strange form of medieval torture that has little or no use in bonsai.
With the two outside legs ‘gripping’ the branch, the middle leg slowly lengthens (by being turned on a screw-thread) bending the branch. These contraptions do produce a tight bend in the branch but I found that however much care was taken (including the use of padding around the ‘feet’) the bark of the branch was always damaged.
I have found that anything that can be achieved with Branch Clamps can also be achieved using coiled wire, guy wires and a little strength or the help of a friend. For these reasons, I avoid using branch clamps!

Branch benders

Branch Bender (image from Gadgets4Bonsai)

A branch bender is a metal lever with two prongs that ‘grip’ the branch allowing the user to exert a far greater load on a branch, causing it to bend into position (where it can then be guy wired).
As with branch clamps, there is a need to protect the bark from being damaged when using a branch bender, it is also possible for the bark to be physically ripped and separated from the wood if care is not taken.

Bending a branch by weakening its structure

The techniques already described in this article increase the possibility of bending thick branches, however, when a branch is so thick or brittle that it can still not be manipulated into position, it’s structure must first be weakened to make bending easier.

Part Two of this article addresses Notching

Part Three will describe the techniques of splitting, hollowing and channelling branches in order to bend them.