Those who are newly interested in the art of bonsai are often unsure about what tools are necessary to begin developing their bonsai skills. Three or four basic tools will equip one to perform most of the tasks necessary to produce and maintain an intermediate to advanced bonsai collection. It is the intent of this article to discuss the useful characteristics of basic tools and some of the more advanced, and less frequently used, tools in order to help neophytes decide which tools are needed right away and which can wait for later purchase.
THE CONCAVE PRUNER
The single most important bonsai tool is the concave pruner. Its primary function is to remove branches in a manner that promotes rapid and smooth healing of the wound. Its name comes from the shape of the cut and wound left on the woody trunk or branch. When properly used the concave pruner leaves a wound on the trunk that is taller than it is wide and slightly concave. The characteristic shape of the concave pruner wound makes use of the fact that wounds on the trunk of trees heal in from the sides rather than from the top and bottom. The concave depression into the trunk allows the wound to callous over without creating an undesirable bump on the trunk. The 8-inch concave pruner is the most versatile size.
The geometry of the cutting edges of the concave pruner is very precise. This allows one to use the pointed end for pruning very tiny limbs and even individual leaves. To preserve this precise geometry, concave pruners should never be forced by cutting material that is too large or too hard. A general rule is to never cut material that is larger than one half the size of the pruner's cutting edge measured from heel to tip. The typical 8-inch pruner is about right for cutting branches 1 1/2 inch in diameter or smaller. When cutting near capacity in size or extra hard wood, it is recommended to use the portion of the blades near the heel, rather than near the tip. This utilizes the extra thickness of the blades near the heel as well as the better mechanical advantage resulting from this portion of the cutting surfaces being closer to the tool's pivot.
All tools have a range of useful performance. If the limb is too thick for a concave pruner or has potential of splitting back into the bonsai, make the cut using a saw or large conventional pruner. The cut should be about one inch from the trunk. Then use a knob cutter to nibble away the stub and to contour the final wound surface on the trunk. Use of knob cutters is discussed later.
THE BUD SCISSORS
Bud scissors are the best tools for trimming leaves, buds and small branches. The short blades and finger holes give excellent control, enabling the user to reach into interior parts of the bonsai for trimming with precision. Although primarily used for delicate work, the mechanical advantage generated by the short blades gives consider able cutting power when needed. As the blades of the bud scissors are closed, the shafts of the handles remain apart. This helps prevent inadvertent crushing of other parts of the bonsai by the closing handle shafts.
BONSAI WIRE CUTTERS
Training bonsai normally involves the use of wire to position and shape trunk and branches. Either aluminum or annealed copper wire is used for this purpose. The wire cutter commonly available at the local hardware store are adequate for cutting wire when applying it to bonsai. This is not the case when cutting the wire to remove it from the bonsai being trained. It is good practice to remove training wire by cutting it off. The training wire is in close contact with the trunk or limb. Therefore only the tip of the wire cutter is used to sever the wire. Otherwise the branch may be seriously damaged. Relatively long cutting blades on hardware store wire cutters have very little mechanical advantage at the tips, making wire removal a difficult chore. Those with physical ailments such as tennis elbow or arthritis may find wire removal quite unpleasant with standard wire cutters. Bonsai wire cutters have very short cutting blades. This greatly increases the mechanical advantage of the tool. For years I used a standard wire cutter to save the cost of buying bonsai wire cutters. This was false economy! I can't believe I tortured my elbow for so long over the price of a relatively inexpensive tool.
THE KNOB CUTTER
This tool sometimes called the melon ball cutter has several unique capabilities. It is a valuable addition to the bonsai tool kit even though it is used much less frequently than concave pruners or bud scissors. The cutting blades of the knob cutter are shaped somewhat like two halves of a sphere coming together. The shape allows the tool to aggressively bite into wood. Protruding stubs are easily and quickly nibbled away by the knob cutter in a controlled fashion. It can remove lots of wood quickly yet is precise enough to shape the final surface cut on the trunk or branch. An additional use of the knob cutter is the removal of undesirable root or trunk material in the area of a partially removed tap root. The aggressive nibbling ability readily removes excess callous underneath the trunk where lack of space makes it difficult to use other tools. No other tool is as effective and clean in performing this task which is often necessary to properly fitting the bonsai to the pot. If used in this manner, the knob cutter should be protected by carefully avoiding blade contact with soil or anything else that might contain hard particles such as grit or stone. The root area is usually quite damp so the tool, especially blades, should be wiped clean and dry with an oily rag immediately after such use.
Soil removal and untangling roots is a regular part of the chore of repotting. A chopstick or something similar is often used, especially with small size bonsai. When the bonsai artist works with medium and large size material the need for a more efficient and substantial tool arises. A variety of root hooks with as many as three points (hooks) are available. In this case, less is definitely better than more. The single point tools are superior in getting the job done with minimal damage to fine roots. Multiple point tools are slightly better for soil removal but tend to do much fine root damage due to the tendency of roots to get tangled in the multiple points.
THE ROOT CUTTER
When potting untrained material for the first time, one almost always needs to remove or shorten large roots. A number of tools can perform the needed cuts including concave pruners. The risk of damage to the tools is high because of the likelihood of small stones getting caught in the blades. The root cutter has thicker, coarser blade construction that is more resistant to damage from small stones. An additional use of the root cutter is for rough pruning of branches that are too thick and tough for the same size concave pruner. The cut is made a safe distance from the trunk and then nibbled down to the desired shape with a knob cutter. Use of this tool is much less frequent than the use of concave pruners but it is quite helpful when needed. Cheap imitations of the famous Felco pruner will do most of the same things but will not be as resistant to stone damage. I prefer the root cutter made for bonsai purposes.
Beyond the basic tools there are numerous other tools and devices that can be useful in certain circumstances. Among these are saws, brushes, tweezers, pliers for jin and wiring, gouges and other carving tools, jacks and bending levers. Purchase of these items is best reserved when it is clear that they are needed to justify the cost.
Ideally bonsai tools should be cleaned and oiled after each use. Turpentine is excellent for removing sap buildup on the blades. After cleaning, the tool should be wiped with an oily rag, giving special attention to the cutting surfaces of the blades. Be careful - the blades are very sharp. Most of us are not disciplined enough to clean and oil our tools after each use. If one falls into this category, be sure to perform this important chore after any use that subjects the tools to unusual
amounts of sap, moisture or perspiration. Tools that are stored where they are subjected to wide temperature and humidity variations corrode at an accelerated rate due to moisture condensation.
A complete set of bonsai tools is not necessary for the beginner. Start with a concave pruner and perhaps a pair of bud scissors. Purchase other tools as expertise and requirements increase. When it becomes clear that one has more than a passing interest in bonsai, wire cutters, knob cutters, a root hook and root pruners will soon be added to the wish list.
Quality and price of bonsai tools vary over a wide range. What to purchase is a personal decision but I offer my thought here for your consideration. My experience has been that the poorest quality Japanese bonsai tools are consistently superior to those made anywhere else. I buy only Japanese bonsai tools. There are several grades of tools made by several Japanese companies. The best are breathtakingly expensive, even for those who have a serious bonsai interest. Although I own and use some of the most expensive tools, I find that the functionality only slightly superior to the less expensive "entry level" Japanese tools.
The nature of the art of bonsai dictates that the tools will invariably be used out of doors where unlike fine woodworking tools they are subject to substantial doses of moisture, corrosive perspiration, and the ever present threat of being lost. Even if misplaced only a day or two, the outdoor environment is likely to cause serious deterioration of the exposed working surfaces of the tool. Tools are offered that are made of stainless steel or are plated with a corrosion resistant layer. I have found the corrosion resistance of these "silver" tools a pleasant feature. Unfortunately I have felt that the sharpness of the blades on the "silver" tools not as good as tools of black steel and the "silver" tools are two to three times more expensive.
If one uses bonsai tools properly, the cutting surfaces will last for years without need for sharpening. Corrosion and abuse will greatly degrade cutting performance of a bonsai tool. Concave cutters, knob cutters and root cutters have fairly complex blade geometry which makes proper sharpening beyond the capability of most bonsai artists and most professional sharpeners as well. With the possible exception of bud scissors, sharpened bonsai tools seldom approach the performance of new tools. With these thoughts in mind, I usually limit my investment and use the least expensive grade of Japanese tool that I can tolerate. It is then much easier for me to accept the replacement made necessary by the inevitable loss, deterioration or abuse that my best intentions are unable to avoid.
Edited for the Internet by Thomas L. Zane