Part 11 of a series by Eugene Howell
One of the techniques that beginning bonsai artists find hard to understand is how to develop leaf pads. Questions concerning this come up more than any other when we work with newcomers to the hobby. So let’s take the time to discuss a couple of the key points in developing bonsai ramification since this is key to having good leaf pads.
Ramification is the repeated division of branches. As a tree grows in nature, the original branches divide and begin growing secondary branches. These in turn divide to produce third and forth branches, and so it goes until the tree is fully grown and covered with thousands of small twigs. By this time each of the tree’s main branches might themselves be branched six or more times before terminating at the leaves. When one looks at the canopy of a tree in nature, you see tens of thousands of leaves held by thousands of small twigs.
The challenge to the bonsai artist, whether beginner or highly experienced, is to force the bonsai tree’s branches to branch. To create, from a main branch coming off the trunk, second, third, fourth and even fifth branches. This is ramification. Each of these small branches will produce leaves and when the primary and secondary branches are wired to form the desired shape, these create leaf pads. Of course, not all styles of bonsai have leaf pads.
To better understand the development of good bonsai ramification, think back to my previous posts about how the various parts of a tree work. The cambium layer, growing beneath the bark, is the layer whose cells have the ability to change and become any part needed by the tree. They can grow into leaves, roots, branches, bark or flowers. These cells are called meristem cells. In creating ramification on our bonsai trees, we’re trying to get the cambium layer to begin developing new branches.
The secret to doing this is contained in the fact that at the base of each leaf petiole (stem) there is a dormant bud. This bud is dormant because the meristem cells at the growing tip of the branch produce chemicals that keep most of the preceding buds along the branch from growing until their needed. If these dormant buds can be coaxed into activity, some of them will develop into new branches.
By pinching off the tip of each branch we can remove this chemical inhibitor and permit the buds further down the branch to begin growing. This paves the way for at least some of the buds at the bases of each petioles to start growing. Not all of the buds along the branch are viable, nor will all of them take this cue to begin growing. Therefore, we need to leave 2 leaves on every twig when we pinch off the tip. The buds that do begin to grow will produce a secondary branch. When these new twigs have four to five leaves, repeat this process so that the same thing happens again as those develop new twigs. Before long you’ll discover that you’ve got a bonsai with excellent ramification.
To turn this ramification into attractive leaf pads all that is needed is wiring to roughly form the shape of a rudimentary triangle. This can be a tedious task when done for the first time and when it comes time to remove the wiring the task is even more tedious, but use patience and keep at it. Once the pads have been shaped, the job of keeping them that way requires only periodic pinching whenever a twig begins growing out of the desired outline.
Bonsai ramification is not difficult to obtain, it just requires a little practice and a good deal of persistence.
Photo credit: flickr Creative Commons, Dwarf Procumbeus Juniper (Juniperus chinensis) by Cliff1066