Shaping Techniques
Copper wire which has been annealed in a fire to make it more flexible is the traditional tool
used in the bending and shaping of branches on a bonsai. It is, however, not the only method
of “training” a bonsai’s branches and trunk into the desired position.
Wire & Its
Use In Bonsai
By Randy Clark Charlotte, NC
Wire is placed on the trunk and branches of bonsai
for one purpose... to assist in making branches and trunks
bend to the desired location. Like a hammer or a screwdriver, wire is a tool designed to accomplish a specific
task in the most efficient manner possible. When it has
served its purpose, it is removed.
Interestingly, a segment of the population seems
determined to believe that wiring a bonsai is the key to
some sort of ancient Asian secret for keeping the tree
small. People have ask if the purpose of the wire was to
cause the tree great pain. They were sure that the creation
of bonsai had something to do with the ancient Chinese
practice of binding the feet of noble women. When I would
smile and patiently explain what the wire was actually used
for they seemed.... somehow.... disappointed.
Wire serves the same purpose as braces on a child’s
teeth. It is a temporary shaping device designed to be
removed after it has done its job.
The objective is to bend trunks and branches. In
most situations wire is the simplest and quickest way to
get that job done. However, it is certainly not the only way
to bend a branch. Other methods include: tieing branches
to the edge of the container with string; hanging weights
from the branches or using trunk jacks and branch clamps.
It should be remembered that the objective is to move the
branch. How that task is accomplished is of secondary
consequence.
material being shaped; the thickness of the branch and the
extremity of the bend involved.
In fact, the use of wire in bonsai is not even mandatory. One school of bonsai in China known as the Ling
Nan School, prohibits its practitioners from using wire.
Ling Nan proponents insist that the use of wire gives the
tree too much of a finished/refined appearance and that
a more natural and pleasing effect can be achieved by
simply clipping and growing branches.
Pines, for instance, are soft wood trees which are full
of sap. They grow slowly and often take a long time before
they can put on enough new wood to hold their position.
Junipers on the other hand grow vigorously and will adapt
to their new shape quickly. Some trees will take a month,
some a year. Unfortunately, the only way to know for sure
is to remove the wire and see if the branch remains where
it was placed. If it does not, it must be rewired.
While this artistic viewpoint has some merit, most of
us will, at one point or another, wish to alter our bonsai’s
appearance by bending a branch using wire.
On the surface, the process sounds deceptively
simple. 1. Put wire on tree. 2. Bend branch to desired
position. 3. Wait for branch to harden in that position. 4.
Remove wire from tree. Nothing is as simple as it first appears.
For beginners, wiring can be a frustrating experience,
but with practice and time comes control and precision.
Eventually beginners discover a fact that experienced
bonsaists already know. Wiring is one of the most relaxing
and enjoyable processes in the creation of a bonsai.
Understand The Task
Understanding the growth habits of the particular
variety of plant material being shaped is one of the keys
to success. Once a branch has been wired and moved to
the desired position a certain amount of time is required for
the branch to “harden off” before the wire can be removed.
How much time will vary and is based on the kind of plant
The damaging
effect of wire
which has been
left on too long
can be seen in this
photograph. The
branch begins to
“absorb” the wire
and when it is
removed, unsightly
wire marks remain.
It is worth noting that some species of plants are
such vigorous growers they will defy any attempt at shaping with wire. Weeping willows and Alberta spruces are
two excellent examples and can be depended upon to
move branches back into their original positions within
days, if not hours after having their wire removed.
A Word Of Caution
Because one can never be absolutely sure how long
to leave wire in place, bonsaist will often leave wire on the
tree for as long as possible. This can be very dangerous.
It is possible to destroy a good piece of bonsai material by
doing so.
If left on for too long, the branch will begin to grow
into and around the wire. As it does it will leave spiral
shaped marks on the bark. Horticulturally speaking, the
tree could care less about wire marks. In most cases it will
eventually absorb the wire and keep on growing.
However, from an artistic standpoint wire marks are
a disaster. The objective in bonsai is to replicate nature’s
patterns. Nature does not leave wire marks on her trees.
Neither should you. Wire marks are a sign of bad artistic
technique because they indicate that the artist was not
doing his/her job. When such trees are entered into
a competition judges will certainly deduct points for wire
scarred trees.
Obviously it is good idea to watch a freshly wired
tree closely. If the wire starts becoming too tight, remove
it immediately, even if it means the branch will not hold its
shape. The wire can always be reapplied later in a different position.
Trees can generally be wired and shaped at any time
during the year. Extensive wiring in the early springtime,
however, should be avoided. Most plants get a vigorous
spurt of growth during this period and will develop wire
marks quickly.
Also remember the majority of trees send their most
vigorous and active growth to the top of the plant. The
horticultural term for this habit is “apical dominance”. It
means that branches in the upper regions of the plant are
enlarging faster and will therefore be more inclined to develop wire marks more quickly than lower branches.
What Kind Of Wire To Use
Generally speaking any type of wire can be used to
shape a bonsai. The objective is to bend the branch and
any means used to achieve that end is permissible. Practically however copper and aluminum wire have become
the standards.
Both types offer sufficient holding power when used
in the correct gauges and both are pliable and easy to
apply to the tree. Copper wire develops
a dark patina and aluminum wire for use
in bonsai comes with a brown anodized
coating to make it darker and less shiny.
Copper and aluminum each have advantages and disadvantages associated with
their use.
coating is removed. A variety of gauges (thicknesses)
will be needed varying from the diameter of a string to the
diameter of a pencil. Thicker wire will be needed to bend
thicker branches, medium wire for medium branches, and
so on. Thinner gauges of wire work fine right off the shelf,
however, thicker gauges of copper wire are so stiff and
difficult to bend that they will need to be annealed in a fire
before they can be used.
Annealing Copper Wire
Traditional Japanese textbooks instruct beginners
to anneal their wire in a rice paper fire. Here in the west,
we’re a little short on rice paper. Actually any good heat
source will work. A barbecue pit, an oven or a plain old
wood campfire will work fine. The business of heating the
wire causes molecular changes to occur which make the
wire softer and easier to bend.
What happens from a physics standpoint is that the
normal positive/negative alignment of the molecules in
the wire become scrambled by the heating process. This
causes the wire to become softer and more pliable. The
flexing process, which occurs the first time the wire is bent,
causes the molecular alignment to return and the wire
instantly regains its former rigidity. This means that annealing the wire will make it easier for you to wrap around
the branch, but as you do so, it regains its original hardness and strength for holding the branch in place. This is a
positive advantage.
A word of caution to those attempting the annealing
process for the first time. The wire must be heated ONLY
until it glows red and then immediately removed from the
fire and allowed to cool slowly. If the wire is overheated it
Copper Wire
Solid core copper wire has twice the
holding power of aluminum and is the traditional substance used for shaping bonsai.
For many years it was the only type of wire
available and for many bonsai purists it is
still the only wire to be used.
Solid core copper is the same type
of wire used to route electrical power
throughout a home. Obviously, the plastic
Aluminum wire used in bonsai is exclusively imported from Asia. It has an
anodized coating on it which makes it aesthetically less noticeable when
applied to the tree. I
will crystallize and will crumble like uncooked spaghetti
the first time it is flexed. Ruining wire in this way can be
annoying. In fact, it was one of the reasons we began
looking into the use of aluminum wire.
Aluminum Wire
The aluminum wire used for bonsai has an anodized coating on it to make it aesthetically harmonize with
the bark of the tree. Anodized wire is not required for
bonsai, only preferred. This earth tone blends better with
the bark and makes an extensively wired tree seems less
unsightly. Anodized aluminum is entirely imported from
Asia and is available only through Bonsai suppliers.
Aluminum is a considerably softer metal than copper. Because of this aluminum has become the preferred
wire among Japanese azaleas growers. Azaleas have
thin bark which damages easily. Softer aluminum is less
inclined to injure these more delicate trees. Copper wire
can also be used on trees with tender bark, but is usually wrapped in paper or raffia to provide a soft cushion
between tree and wire.
In addition to its softness aluminum wire’s one great
advantage is that it does not have to be annealed. The
great disadvantage is that it has half the holding power
of copper. That means the diameter of any wire used to
bend a branch will be twice as thick when aluminum is
used as it will with copper.
Aluminum has one other advantage which, at the
same time, can makes it a little dangerous. When the
time comes to remove it, aluminum can be very carefully
uncoiled from the branch, straightened and reused on
another tree later.
The use of a branch clamp is one alternative to wire and
allows the artist to gradually achieve the intended curve over
a long period of time, thus reducing the change of breaking
the branch.
Copper, because it regained its rigidy in the application process is somewhat more difficult and is usually
removed in small pieces with a bonsai wire cutter. We all
like to save money, but consider that uncoiling any kind of
a wire runs the risk of accidentally snapping and breaking
branches. Our recommendation is to decrease the chance
of breaking branches by cutting off all wire, whether it be
copper or aluminum.
How To Apply The Wire
Learning how to correctly place wire on a bonsai
is largely a matter of practice... And practice will make
perfect. An experienced
bonsai artist can bend and
shape their creation using a
minimum of wire. Beginners
trees often look as if they
were caught in an explosion
at a spaghetti factory. Effective technique comes from
practice and experience.
This comes with time. Technique and tidyness are important, but the objective is to
shape the tree. Extensively
wired bonsai are “in training”
and are not supposed to be
showpieces. That comes later after the wire is removed.
into and damages the bark. You should not be able to
see daylight between the wire and the bark. Loosely
applied wire will increase the risk of cracks or stress
fractures in the branch.
5. Wire needs to be coiled at about a 45 degree
angle perpendicular to the branch or trunk and placed
snugly up against it. An angle of about 45 degrees
seems to provide the best holding power. Wire coiled
too close together will tend to behave like the spring on
a screen door and will want to “spring” back. Wire coiled
at an angle greater than 45 degree may leave such wide
unsupported sections of the branch exposed that breaks
and cracks may more easily occur. This is a critical
consideration on heavier branches, but becomes less
critical with smaller branches.
Correct placement of wire on a bonsai is largely a matter of
practice and practice makes perfect.
It is important to try and get as organized as possible.
Developing a technique with which you are personally
comfortable is best. Be neat, organized and try to apply
the minimal amount of wire in such a way that it does the
maximum amount of work.
Some bonsai artists like to completely wire all the
branches on their tree first and then bend them to the
desired positions. Still others like to wire one branch at
a time, bend it into position and then proceed to the next
branch. Some like to start at the top of the tree and work
down... others at the bottom and work up. It is all personal preference. There are, however, some guidelines that
should be observed:
General Guidelines For Placement Of Wire
On A Bonsai
1. If you are unsure about whether or not to remove
a branch, it is usually better to wire the branch and try to
work its placement into the final design than to cut it off.
The branch can always be removed after the fact .
2. Always begin with the thickest branches and the
heaviest wire first. Gradually work toward thinner branches and thinner wire. This will greatly assist in the task of
keeping the wire placement organized and orderly.
3. Avoid crossing wires when possible. Follow previous strands up the trunk and out the next branch. The
result will be increased holding power and a much more
professional appearance.
4. Wire needs to be applied so that it is snug against
the bark with no spaces or gaps, yet not so tight that it cuts
6. When wiring any given branch you have the
choice of applying the wire in a clockwise or counterclockwise direction. Plan what you are doing. Don’t
simply “throw” wire onto the tree. If your plan is to move
a branch down and to the right then placing wire on the
branch in a clockwise pattern will cause it to tighten slightly
during the bending process. Counterclockwise placement
would cause it to loosen slightly and therefore lose holding power. Think about what direction you are wiring and
how you plan to bend the branch. Again, this is a consideration which is more critical for thicker branches than for
thin ones.
7. Any given piece of wire applied to a tree needs to
be secured to some other part of the tree if it is expected
to hold when bending pressure is applied. A piece of wire
has two ends. Always attempt to wire two branches (of the
same diameter) with one piece of wire. When doing this
make sure that the wire makes at least one circumference
of the trunk (more if necessary) before going out the next
branch. This “required” turn around the trunk will insure
that when branch #1 is moved, it will not cause branch
#2 to also move. Instead, the “torque” will be against the
trunk and not the other branch being wired. If you have
only one branch to wire, secure the opposite end with a
couple of wraps around an adjacent branch.
8. When applying wire always support the branch
being wired with the thumb and forefinger of your opposite
hand. Bring the wire to the tree and rotate the wire slightly
as you wrap it about the branch. This rotation will cause
it to seat more snugly against the branch. When working
with very thick wire you will find a pair of wire pliers handy
for assisting with this task. When that wrap is complete,
inch forward with your thumb and forefinger and support
the next section as you apply the next wrap. Continue in
this manner until you have reached the end of the branch.
This technique guarantees that the branch will always
have the solid support of the artist’s hand as the wire is
moved into place and that unnecessary breaks will be
avoided.
9. Place wire on the outside of any intended curves
or bends you plan to make. When bending a branch the
wood of the tree is compressed on the inside of the curve
and stretched on the outside of the curve. Placement of
wire along the outside of the curve provides critical support
where it is most needed.
10. To determine the correct gauge of wire needed
to hold a branch securely in place you can try pushing on
the branch with an extended piece of wire about 8 or 10
inches long. As you “push” against the branch you will
discover that: 1. the branch will move, or 2. the wire will
bend. If it is the wire that bends, it is probably of insufficient strength to hold once coiled into place. Go to the
next thickest diameter and repeat the test. At some point
the wire will remain rigid and the branch will move. This
is probably indicates you have selected a gauge of wire
sufficiently thick enough to hold the branch securely. Note
that we said probably.
If the branch does not remain in its new position, you
have two options: 1. remove the wire and replace it with
a heavier gauge that will hold, or 2. Place another strand
of wire on the same branch by coiling it alongside the first
one.
The development of good wiring technique is dependant upon practice more than any other thing. Remember
that if the branch goes where you bent it and does not
break... you did it correctly. Admittedly you will probably
use more wire than necessary in the beginning and its
organizational structure on the tree will look a little like a
roadmap in the mountains, but with time and practice your
technique will improve.
NOTE: This article and images it
contains were written and photographed
by Randy Clark, resident bonsai artist at
the Bonsai Learning Center in Charlotte,
NC. They are intended for private use
only. Reproduction of this material for
commercial purposes is strictly prohibited
without the written consent of the author.
© 2000 Bonsai Learning Center, All Rights Reserved