The Art Of Tiny Leaves
One of the joys of working with bonsai trees is that the hobby truly is an art form. Anyone who has worked extensively with bonsai knows that the cultivation, shaping, and care of these special plants take an extreme amount of patience, knowledge, and an eye for artfulness.
Most people know that the purpose of a bonsai tree is that the beauty of a fully-grown, aged tree is mimicked in miniature. Not only is the trunk of the tree miniaturized by specific selection, planting and pruning techniques, but so are the leaves. Without a process to encourage the growth of miniature leaves, then the bonsai tree would appear to be off-balance, and the scale of the leaves in comparison to the overall plant would completely ruin the artful effect of realism.
Many wonder how to keep bonsai tree leaves small. There are several techniques that the bonsai artist can implement that will hopefully result in a balanced bonsai specimen with the tiny leaves that are so prized. As with most things, nature is not perfect. It can be erratic. What will work for one tree may or may not work for another. However, by implementing methods that have been tried and true among bonsai enthusiasts for centuries, you dramatically increase the chances of producing, in time, the miniature leaves that are so prized among bonsai aficionados.
Use Small-Leafed Varieties
Often, the initial selection of a tree variety, or even of an individual specimen, can dictate the eventual size of the leaves. In nature, there are trees that naturally tend toward smaller leaves, and there are trees that tend toward bigger. When selecting a plant to work with, be conscious of this and let nature work for you instead of against you. Trees such as the Linden, Elm, Ash, Willow, or Oak tend towards leaves that are small, even when growing under normal circumstances in the wild. This tendency will make these specimens more prone to smaller leaves once they become bonsai. A large-leafed specimen, such as a Sycamore or a Magnolia, may provide significantly more challenging as bonsai raw material.
Keep Bonsai In Bright Light
Most bonsai specimens thrive in bright lighting conditions. If you want to encourage smaller leaf size, then it is critical that your bonsai be exposed to lots of natural sunlight. Place your bonsai outside where it is in direct sun. It is possible to grow many bonsai in indirect lighting situations, but it is less than ideal. The plant may survive, but it will have a tendency to larger leaves and will grow leggier in an effort to collect as much sunlight as possible. When a plant is grown in low light, it will respond to this by producing as much large foliage as possible. This foliage allows it to collect as much energy as it possibly can.
In contrast, a bonsai grown in direct sunlight will have no need to increase its leaf size to gather in energy. When a plant has an abundance of available light, there is little incentive for it to waste resources in expanding leaf surface area. Therefore, the result is a tree with smaller leaves that grow in more compact clusters. And this is exactly the look that most bonsai artists seek.
Defoliate In The Spring
If your bonsai is well-planted, settled in and in good health, it may be a good idea to consider defoliating. Defoliating consists of removing some or all of the leaves. It is critical, however, to research first whether your plant can withstand defoliation. For example, this would only be a method to employ with deciduous plants that lose their leaves on a regular seasonal basis (such as Chinese Elm or Ficus). NEVER defoliate bonsai trees that are conifers (such as the Juniper), as they are supposed to retain these leaves and will never recover.
Because it is shocking to the plant, it is important that defoliation is only done on a healthy tree, and that it only be done in mid-spring. The reason for this is that you want to remove the first leaves of the spring season, but you want it done early enough that the tree has enough time to develop a new set of leaves.
The best way to defoliate (or to partially defoliate, if you want to go the conservative route) is to remove leaves by carefully cutting them with shears that have been sterilized in alcohol. When defoliating, be careful to remove the leaf right at the base of the leaf itself, and to leave the petiole (or stem) attached to the branch. Allow this stem to fall off naturally as it dries up. Soon, new leaves will sprout and you will be delighted to discover that they are often smaller than what was there before. Be careful, however, that you do not defoliate your tree more than once a year.
Over time, correct defoliation will result in smaller leaves that eventually will be two-thirds smaller than the leaves of a full-sized specimen.
When combined with proper bonsai planting techniques and proper selection of specimens, a consciousness toward lighting conditions and defoliation can result in beautiful miniature trees with the tiny, compact leaves that all bonsai growers are sure to love.