Presented below is a review of wiring techniques and principles that has appeared in a number of books along with some personal experiences.

There are a couple of points to understand before you begin wiring a tree:

1.  The sole purpose of wiring a bonsai is to change the direction and shape of the branches and trunks and      make them conform to the owner's concept of the perceived design (1). Therefore, before you begin,      you should have a basic concept of what you want the tree to look like when the tree is "finished".
2.  The way that wiring works is that, in bending the wood, you stress, and sometimes damage the cells.      The tree, while repairing the damage, grows into the shape imposed on it by the wire.
3.  Wiring is stressful for a tree; and if you wire a weak branch or tree, you may lose the branch or even the      tree.
4.  There are proper methods to wiring (these will be discussed below).
5.  The best time to wire is dependent on the type of tree but is generally considered to be late winter or      early spring. As we will see later, this may not be the best for the tree.

Wire Type
Before we begin the discussion of wiring techniques, we need to discuss the type of wire to use. Bonsai wire is available in copper or aluminum. Aluminum is available in two types, Plain (Silver), and 'Anodized' (where the wire is given a brown coating). I haven't seen any plain aluminum wire in any of the bonsai shops I have visited but that doesn't mean that there isn't some available somewhere. When you ask a fellow bonsai enthusiast about the best type of wire, he definitely will have a preference for one over the other. As with most things, there are advantages and disadvantages for either.

Copper wire is annealed (controlled heated to soften it and make it easier to bend). It should be stated that trying to anneal copper wire at home is not recommended, since the wire can be overheated and become brittle or even melted. Copper wire is generally more expensive than aluminum. However, copper is somewhat stronger than aluminum and a thinner gauge of wire can be used vs. aluminum. When you put the copper wire on the branches, it becomes "work hardened" and becomes very stiff, thus holding the branch. As the copper ages on the tree, it turns a darker color and becomes less obtrusive to the appearance of the tree. However, sometimes copper wire (due to environmental conditions) will develop a green patina caused by oxidation of the wire (technically called verdigris). This oxidative state can be harmful to some types of trees - especially stone fruits.

Many bonsai enthusiasts are now using aluminum wire because it is cheaper than copper and is somewhat easier to wrap onto the limb. However, since aluminum is weaker than copper, it requires a larger gauge. There is also the idea that there is more capability for "stretch" with aluminum; so that as the tree grows, there is less chance of cutting in and scarring of the bark (2). I personally don't agree with this idea since use of either aluminum or copper can cause scarring if not done properly or if left on for too long a period of time. Aluminum can also be toxic to some varieties of trees, but if the aluminum is anodized this is a minor problem.

Wire Size
Bonsai wire is available in different sizes from 1.0 mm to 6 mm. There is no set rule on what gauge of wire should be used for a particular branch or trunk thickness (3). It is normally suggested that the wire gauge (thickness) should be about one third of the diameter of the section to be wired. The decision on wire gauge also is dependent on the degree of bend desired. If you will be making a drastic bend, a heavier gauge will be required than if a minor bend is implemented. For drastic bends, you may want to consider using multiple wires which will require a slightly smaller wire gauge but will require more patience in putting the wire on the tree.

A way to determine the proper wire size that I use is to hold a wire, which you believe to be the proper size, about one inch from the end of the wire and push on the branch you are going to bend with the end of the wire. If the wire bends, you will need to go to the next larger size. If the branch bends, then you may have the proper size wire, or perhaps too large a wire. Try going one size smaller and repeat the experiment until the wire bends, then move back up one size.

If you underestimate the gauge of wire, there is not much of a problem. You can simply get another wire and wire it parallel and as close as possible to the first wire, without crossing wires at any point. The important thing to watch is that the wires are very close together and do not cross each other. A number of 'experts' sometimes recommend that it is better to use two strands of wire rather than a larger single gauge as the pressure of the wire on the branch is more evenly distributed and the wire will not cut in the bark as quickly. For more drastic bends this is probably correct. However, for smaller branches, it is sometimes difficult getting one wire on correctly, let alone two!

Coussins (4) recommends the use of multiple wires for new material and even suggests leaving a small gap between the two wires in case you need to remove one of them. He also suggests using multiple wires when a number of branches or twigs need to be styled on one limb.

Some Things To Consider
If you are trying to wire a soft-barked tree (such as a cork bark variety or if you are new to wiring), wiring can be very difficult without damaging the bark. To solve this problem, you have two options. The first is to wrap the wire with something such as florist tape to protect the bark (procedure below). The second is to wrap the branch with raffia (detailed below). Both have their pros and cons. If you are wiring when you can get a good view of the branch (i.e. when the tree is dormant), raffia is probably the best choice. If you are wiring when the tree is budding or are wiring a conifer, wrapping the wire prior to use works well.

When wiring, consider the tree's individual characteristics. Some trees are easier to wire at certain times of the year. Different parts of a tree will vary in the length of time necessary for the branch or trunk to set in the desired place. Some varieties will tolerate drastic wiring and others will not (5).

The amount of time to leave the wire on is dependent on several variables. One is the size of the limb or trunk being wired. If the size is ½" or less, the time should be about 12 to 16 weeks. If it is over ½", it may take as long as two years. If the wood is pliable (like a tropical), it generally takes longer but is more prone to scarring by the wire. If the wood is more brittle (like a pomegranate) it may take as long as 6 months. To prevent breaking brittle branches, you can "massage" the limb. To do this, you hold the branch starting from the trunk and with the thumb and forefinger work the limb toward the tip. You may have to do this a number of times to get the branch pliable enough to bend it. If you let the tree dry down, the cells of the branch are easier to bend since they are less "turgid".

When wiring, it is better to leave the wire on longer than you think is necessary, as long as it is not cutting into the tree. Sometimes the tree will revert back to its original form over a period of a few weeks, so it is better to wait as long as possible to ensure the tree is set.

Avoid twisting the branch or trunk. Think about the bend you want to accomplish and bend it once as you wire.

DO NOT wire a weak tree! It will only cause more problems.

Best Time To Wire
If you read various bonsai books, most authors recommend that the tree be wired in late winter or early spring. However, wiring can be done at almost any time of year. Each season has its advantages and disadvantages. Generally, major wiring is done at the time of pruning, for easier access.

Spring: With spring, the plant is starting its active growth cycle, and it is easy to break off a delicate branch when wiring or to damage the soft bark. It also must be realized that the trunk and branches are thickening quickly and the wire can quickly cut into them. Care will therefore need to be exercised so that the wire is not exceedingly tight when first wrapped. Periodic monitoring of the wired tree will need to be done to ensure that the wire is not cutting into the tree. The advantage of spring wiring is that the tree is developing new cells around the trunk and limbs while they are being held in their new positions, thus helping the process considerably.

Summer: This is a time when the cambium is full of sap and this makes it easy to cause separation of the bark from the wood if drastic bends are made. Smaller branches are more hardened at this time versus spring and may be wired more easily. One of the main disadvantages for this time of year is that the tree is full of foliage, which gets in the way. Also it is difficult to wire without catching the leaves under the wire. Catching foliage under the wire must be avoided since it can rot when bunched up and may cause other problems, including making an ideal nest for insects. From an aesthetic point of view it also looks messy and unattractive. If some foliage should get caught under the wire, it needs to be removed immediately.

Autumn: Wiring at this time of year generally shouldn't be done since the tree is starting the process of setting new buds for next year's foliage or flowers.

Winter: For deciduous trees, this is the ideal time to wire since there is no foliage and you can get to all the branches quite easily. Remember, though, that buds should be treated with great respect and all care should be exercised not to knock them off. The wood on the trees can become quite brittle at this time of year and bending has to be done with caution. Since the tree is not thickening at this time of year, the wire can be left on longer without risk of scarring the wood. Also as the sap is draining down at this time of year, the setting of the limb or trunk is somewhat aided.

Wiring Aids
Florist tape, obtainable from craft stores and some florist shops, is a thin green tape that is on a spool similar to ribbon. The process is quite simple. Cut the length of wire needed to bend the desired branch and starting at one end of the wire, start wrapping the tape around the wire in a spiral pattern. I generally wrap two turns at first and then start the spiral pattern. The key here is to pull the tape tightly so that it stretches slightly - but don't pull so strongly that you break the tape. You want the wire completely covered with the tape and no wire showing. I try to overlap the tape with about ¼ of the width of the tape. When you get to the end of the wire, simply make a couple of parallel wraps to secure the tape. This method works with 1.5 mm wire and above.

The tape I have is a dark green and blends with the foliage. The problem I have with this method is if the tape is not wrapped tightly, it will have a tendency to slip as the wire is wrapped around a branch. When I do use this method, I take extra time to make sure that I pull the tape tightly to secure it to the wire. I also sometimes wrap to the end of the wire and then reverse the wrapping to get a better bond with the wire.

Raffia comes from the leaves of palm tree usually found in Madagascar. It can be purchased in craft or hobby stores as well as a number of bonsai stores. It comes in balls, braids, and hanks which, when uncoiled, have lengths about 3 to 4 feet. When dry, it is quite fragile; but when wet is quite strong. Using raffia essentially adds an additional layer of bark which helps prevent cracking and rupture of the natural bark when you bend the branch or trunk. It also helps prevent premature 'biting' of the wire into the branch. Applying the raffia can be tedious, and care must be used to prevent breaking off any buds or small branches. It is also difficult (or impossible for me) when the tree is in full foliage.

Start by taking 5 to 7 strands from the bundle and tie one end in a small knot. Prior to use, it should be soaked about 30 to 40 minutes in warm water - when the strands are thoroughly wet, they will be almost translucent. Using 2 to 4 bundles of wet raffia form a flat ribbon by gently drawing the bundles between your thumb and forefinger. Starting at the end closest to the base or trunk, spiral the ribbon of raffia around the branch while holding down the end piece for several turns before cutting off the knot. Ensure that you are applying the raffia in the same direction that you will be applying the wire. Support the branch with your left hand while your right hand pulls the raffia ribbon around the branch tightly (or the reverse if you are left handed). During this process, you need to support the branch carefully so as not to break the branch. The tighter the raffia is, the better it will support the bending later on. As mentioned above, you have to be sure not to capture any foliage under the raffia.

Continue wrapping the raffia all the way to the end of where you will be applying the wire. When you do reach the end, you can tie several strands of raffia to hold it in place until you start applying the wire. The wire should be applied before the raffia dries. Also after wiring, the raffia should be wetted during the daily watering. It will keep the underlying bark moist and protect any hairline fractures that occurred during wiring.

I personally only use raffia on trunks or very soft bark because it is a difficult task to learn. I prefer to use the florist tape on smaller branches because you only have to wrap the branch once - with the wire coated with the florist tape.

Order of Wiring
In order to make wiring easier, Murata states (6) there is a general order for wiring trees. Since older trees have more branches, the wiring process can become rather complicated if a fixed order is followed. Therefore, with older trees, simply start from wherever is easiest. For those branches that are more difficult to reach, you can simply leave them until last, which assumes that some of the other branches will be bent out of the way so that the more difficult branches can be reached. For young trees, you should start at the bottom of the trunk and gradually move upwards. After wiring the trunk, wire the first branch from the base to the tip. Then wire the first twig on the first branch, from the base to the tip. Proceed to the second twig on the same branch and so on. When you have wired all the twigs on the first branch, repeat the process with the second, third and fourth branch. Finally, start wiring the top, beginning at the base and proceeding to the tip. Looking at Figure 1 (7) will show the basic flow of wiring.

Figure 1

Wiring Techniques
As with all bonsai procedures, there are "rules" to wiring. For wiring, they are rather simple. We won't list the rules in any simple form. If you read the following techniques, these rules will be covered in the description. Your first (or even second) wiring may not look like a professional did it. However, since the wire will generally only stay on for a short period of time, you will have many more opportunities to improve your techniques.

Figure 2

The best wiring is evenly spaced, has no crossing wires, is unobtrusive and has the end of each wire before or at the end of each branch (Fig 2) (8). The most important thing to remember is that the start should be secure to either the trunk or to a branch. Wiring should be slightly tight but not too tight or there won't be any room to grow. If it is too loose, there will be no strength and the branch will not be held in place. The ideal angle is 45 degrees when viewed from all sides (see Fig 3) (9).

  Figure 3                                                       Figure 4

If the spirals are too close, the wire acts as a spring and will not hold the tree in place. If it is too widespread, strength will be lost. The 45-degree angle makes use of all the strength available in the wire. To determine how much wire will be necessary to complete the job, measure the length of the branch to be bent and add one-third the length. Remember it is better to have more than what is needed, rather than less.

Wiring the main trunk: Anchor the wire by sticking it into the ground at the back of the tree. If possible stick it in the soil behind a strong root for extra strength. The trunk is then wired at 45-degree angle spirals (Fig 4) (10).

Figure 5

There are basically three different modes of branch growth: forked, alternate or staggered, and opposite. The opposite or "bar" branch makes the tree artistically appear too symmetrical in form. Therefore, one branch is usually removed.

Forked - By wiring two branches of the fork with one wire, each branch holds the other. The important thing here is that wiring at the crotch of the fork should be secure and firm (Fig 5) (11). The procedure is to begin at the fork, holding the wire at the back of the fork with one hand and then bringing the wires around and through the fork from the front, to form and upside down "V". Wire a couple turns on one branch and then, after wiring the other completely, return to complete the first one. If you are going to wire only one of the branches, wrap a couple of turns on the one that is not to be wired which should be enough to hold the other. If you are widening the fork, both sides of the fork should be wired. Caution should be used for this procedure since the fork is a reasonably weak point in trees.

Alternate or staggered branches - This is the most common wiring that you will do. When you are wiring, you should try to wire two branches at a time since this acts to secure the beginning of the wiring on each branch. Start by treating the lower branch and the main trunk as a fork (Fig 6) (12). After doing a couple of turns up the main trunk, wire the lower branch. This is the same procedure that you would use if you want to wire only one branch. After wiring the bottom branch, continue up the trunk to the higher branch. Make sure that the first half turn on each branch is parallel to the main trunk.

Figure 6

Wiring forked branch with one wire - The wire is anchored around the main trunk, and the branch is double wired until the fork is reached. The double wire is then divided to wire both branches. This results in a more continuous shape along the entire branch, as well as more security (Fig 7) (13). The problem here is trying to determine what size wire to use. If both branches after the fork are the same size, then wire size selection is easy. If they are not, as is generally the case, you need to select the wire for the smallest branch. If the larger branch (after the fork) doesn't hold, you can wrap another length of wire on it (you will need to start the wire back on the trunk to secure it).

Figure 7

Wiring branches downward or upward - When bending a branch downward, the first half turn of wire should come over, then under the branch (Fig 8) (14). When bending a branch upwards; the reverse is done, that is, the wire approaches the branch from below (Fig 9) (15).

       Figure 8                                                                  Figure 9

Clockwise or counter clockwise wiring - If you are working on a branch on the right side as you look at the tree, counter clockwise wiring will help bring the branch forward; clockwise wiring will help push the branch away. If you are working on a branch on the left side as you look at the tree, the reverse is true. To determine the clockwise or counter clockwise direction, look at the branch from the end back toward its base.

For right-handed people, you will probably find it easier to hold the tree with your left hand and do the wiring with your right hand. Therefore, if you turn the tree around so that you are always working on the right side, the orientation for your hand preference will be correct. You will need to remember the clockwise/counter clockwise directions for right side wiring stated above. For left-handed people, you will be turning the tree so that you are working on the left side. It should be noted that the "forward" and "backward" directions refer to the current position of the tree and not the front and back of the styled bonsai.

Many experts recommend doing both the wiring and bending at the same time. By that we mean applying the wire with one hand and starting the bend with the other. The risks are that you can break off the branch. I sort of compromise. I wrap a section of the branch (usually about one half the length), stop the wire wrapping, bend the branch (using both hands and only that portion of the branch that is wired), then continue the wiring to the end. I then put the final bend on the branch. If at all possible, you only want to bend the branch once to keep from causing severe damage to the limb. If I am trying to bend the trunk, I wrap the whole trunk with the wire, and then do the bending.

When a young shoot develops on the trunk in a place where a branch is desired, wiring should not be done too early, as the shoot may snap off while still tender. However, most buds will begin to grow vertically and the angle so formed at the base of the branch will be unattractive and difficult to correct later on. The solutions are to wire carefully in summer when the shoot is semi-hard or to pull it down with the use of string in late summer.

It is not always necessary to wire a branch depending on the circumstances. If the branch needs to be bent down, a weight can be applied to it to bend it down. The problem is to find the correct weight to get the desired bend. An additional problem is that the weight will 'blow in the wind' and can actually tear off a delicate branch in one of our thunderstorms. Another method to bend down the branch is to attach a length of wire to the branch and secure the opposite end to either a larger branch below or to a wire attached to the pot (Fig 10)(16). The wire can be twisted several turns as needed to bring the branch down. This method doesn't work on new season branches and is not effective on thick heavy branches. An important point is that where the wire goes over the branch to be bent, some plastic tubing should protect the branch.

Figure 10

Even if you do everything right, you may still have a broken branch. If your branch does break while you are bending it, leave it as it is and apply sealing putty. Do not move the branch for the rest of season and it will likely heal. Quite often, if you are making a drastic bend, you will hear the wood cracking. Once again, stop and examine the limb carefully. If you can see any cracks, stop the bending, leave the wire on until it needs to be removed, and wait until next season to continue. If you see no evidence of cracks, it is probable that the wood has cracked under the bark. You can 'carefully' continue the bend, but use extreme caution and listen carefully. If you hear any additional cracking, stop bending and once again wait until next year.

Unwiring
When it is time to take the wire off the tree, the wire should be cut off, not unwound. I have seen several articles where some Japanese masters unwind the wire. Unless you are thoroughly skilled though, this is foolhardy. The wire can't be reused (unless it is re-annealed), you run the risk of breaking off foliage or even the branch you spent so much time trying to bend. Using a bonsai wire cutter is the recommended method. I typically start at the main trunk, cutting the wire from it and then start on the branch. I cut the wire at each location where the wire is 'facing' me. I can then twist the cut wire off the branch with no damage to the branch. One important thing to mention is that even though a bonsai wire cutter is designed so that it will cut the wire and not the branch (take it from me) it can also cut off the branch if you are not careful on small branches.

(1) Koreshoff, Debra. Bonsai, Its Art, Science, History and Philosophy. Brisbane, Australia: Boolarong Press, 1997 pg. 83
(2) Koreshoff, D. pg 84
(3) Koreshoff, D. pg 84
(4) Coussins, Craig. The Bonsai School. Leicester, England: Silverdale Books, 2002 pg 110
(5) Koreshoff, D. pg 85
(6) Murata, K and Murata, I. Bonsai Nature in Miniature. Tokyo, Japan: Shufunotomo Co., Ltd., 2000 pg 70
(7) Murata. pg 70
(8) Prescott, David. The Bonsai Handbook. London, England: New Holland Publishers Ltd., 2001 pg 87 (Modified)
(9) Koreshoff. pg 87 (Modified)
(10) Koreshoff. pg 87 (Modified)
(11) Koreshoff. pg 88 (Modified)
(12) Koreshoff. pg 89 (Modified)
(13) Koreshoff. pg 90 (Modified)
(14) Koreshoff. pg 91 (Modified)
(15) Koreshoff. pg 92 (Modified)
(16)Coussins. pg 111