In the wild, leaves of deciduous bonsai get smaller over time. There are ways to encourage this to happen with our bonsai trees. Below we go over why this is so, and how to shrink your leaves!
Genetics play a big role in the size of your tree leaves, but through restricting growth, you can encourage the leaves to shrink. This is also dependent on species and age.
Bonsai Tree Genetics
DNA is responsible for half of this phenomenon. There’s a certain element of predisposed characteristics for any living thing. Just like us, trees have DNA. No two are exactly the same. They vary in leaf sizes, colors, root strength, and any other attribute. There
The Japanese bonsai artists discovered early, that there were inherited traits and characteristics between trees. So they cultivated different specie and sub-species of individual trees that had desirable aesthetics and health.
Even with this knowledge, there are a lot of bonsai out of Japan with not so desirable characteristics. Some Trident maples have very coarse leaves. Small leaves are hard to achieve on these because of their DNA.
How to Shrink the Leaves
The other aspect is things that are up to us. This basically comes down to restricting the trees growth. We can restrict plant growth through various different ways:
Repotting Frequency
As the tree get’s older, we want to repot it less and less frequently. The goal here is to develop a mature root pull. This will allow mature branches to develop. Once mature branches are developed, then leave size begins to reduce.
Reduce Fertilizing
The trick is to not fertilize to heavily in the spring. This is one of the most common misconceptions in all of bonsai. We are trying to reduce internode length. If you fertilize it in the spring, it will grow like crazy.
Defoliation
Usually around May or June (depending on your location), the leaves have hardened we can remove them and a second, smaller set of leaves. This can’t be done with every species, and it’s a very risky procedure to do with any tree. Once defoliated, the plant has no way to generate energy.
Do not do this unless you live in a place with a ton of sun, and your trees are extremely healthy.