Part 12 of a series by Eugene Howell
Trees live a long time and many of us don’t have 30 or 40 years to wait for a seedling to grow into an impressive bonsai. For those who do, they may not have the patience to wait that long. Fortunately, in the art of bonsai, there are ways to shortcut the process. One of those ways is to create a bonsai forest. One of those ways is to create a forest planting. Typically a bonsai forest will use much younger trees that are not nearly as well developed as a single planted bonsai.
A bonsai forest is frequently set on a natural slab of stone rather than in a bonsai pot. This arrangement often leads the novice to have two questions: “How do I keep the trees in place on a natural slab?” and “How do I prevent the soil from washing over the side when I water it?”
A good bonsai forest planting requires planning. One way is to follow the example of a draftsman; make a diagram of the finished planting showing where each of the trees will be placed and their spatial relationship to all the other trees on the slab.
With an outline of your slab drawn, draw each of the trees. Their placement should identify where the primary and secondary trees will go as well as those that are third and fourth. The primary tree has the thickest trunk and is the tallest. The secondary tree is the second thickest and tallest, etc. The numbers and sizes of the other trees beyond number four, usually don’t matter so long as they are shorter and thinner the rest, only their spatial relationship to the other trees is significant. Well practiced bonsai artists can get their tree placement correct on the first drawing so don’t worry about it if you wear out a pencil eraser moving them around the drawing until you think they look good.
while placing trees in the diagram, keep these few rules in mind. First, never have a tree directly behind another because the viewer won’t be able to see it from the front; but having it a tiny bit offset is OK. The idea is to be able to tell that there’s depth to your forest, even if one trunk is only partially visible.
Second, never have any three trees forming a straight line. Always have them form a triangle. Third, never have the trees spaced uniformly. Have some of them very close together and others more distant. Fourth, for any bonsai forest having fewer than 13 trees, always use an odd number of trees. If you have more than 13 trees, this rule no longer matters. And always have primary, secondary and tertiary trees as described above.
Having reached the point where you’re satisfied with the placement of all your trees, we can now discuss how to keep them in place on the slab. The simplest method is to use plumber’s putty-epoxy. It’s very strong when dry, bonds to relatively smooth surfaces and stays bonded under constantly moist conditions.
After making your trip to the local hardware store for the epoxy, found normally in the plumbing aisle, it’s time to start creating the planting. Mark a spot on the slab where each of the trees will go. You probably should place the trees on each spot to verify that your concept looks good in real life. Hold two or three upright at one time to get a general idea of how they’re going to mesh. If you’re satisfied with your arrangement, cut pieces of 2.5mm or 3.0 mm bonsai wire for each tree and mount one at each of the spots you’ve marked on the slab. Place the center of the length of wire onto your marked spot and cover it with a ball of epoxy about the size of a marble. After you press the epoxy over the wire, make sure it stays motionless until it hardens. This usually takes about 30 minutes. Although the directions with the epoxy say it will work when wet, I have found that I get a better bond if the slab is dry and clean.
With the wires securely attached to the slab, you’re all set to place each tree in the designated position. Twist the wire around each so that it is held upright firmly in the position you wish it to be. All that remains is to add bonsai soil.
If you’ve been around bonsai for any period of time you’ve heard of the term “muck”. This is the miraculous stuff that holds soil to a slab. Essentially what you do is make a small dam that goes all the way around the slab at or near its edge. This dam won’t wash away and is what keeps the soil from doing just that.
Like many things in bonsai, muck can have many different recipes and each experienced bonsai enthusiast has his own favorite. Whatever the recipe, it needs to stay in place and not wash off. It can’t dry out and crack, nor lose its grip on the slab. It must be fertile enough to allow moss and tree roots to grow into it (this is particularly important if you make a forest or penjing planting where trees are planted on rocks).
Some recipes are better than others but the one that I find that comes closest to meeting all these requirements is one that uses a little Bentonite, an extremely fine clay. It’s used in the well-drilling business to line the drill holes in the ground. But pure Bentonite has too many major disadvantages. By itself it’s far too sticky. When allowed to dry out it cracks and after drying out it repels water. It’s to dense for roots and moss to penetrate.
The key to using it for bonsai is to mix it with cow manure and moss. I’ve found that one part Bentonite with 5 parts of the brand name “Black Kow” along with one part sphagnum moss cut into one inch lengths is a great working recipe. The resulting mixture, is still sufficiently sticky, is easy to handle, stays in place, is very easy to rewet if it dries out and can be reshaped on the slab as long as it’s moist.
When you mix a batch, do so in a sealable one or two gallon bucket that way you’ll always have some handy when the need arises.
Forest plantings are a great way to create an outstanding bonsai in very little time. If you need help starting yours, seek out a local bonsai club in your area.
Photo credit: flickr Creative Commons ‘Catlin’ Chinese Elm (Ulmus parvifolia ‘Catlin’) by cliff1066