Trimming Bonsai – Leaf Reduction Techniques

Trimming Bonsai – Leaf Reduction Techniques

Trimming Bonsai is essential to proper branch structure.  Necessary for Ramification and twigging of the branches and foliage.  Different trees have different techniques that work best for them.  Ficus and other deciduous trees need to be trained to create alternating pairs of leaves as close together as possible.  On the other hand Junipers and other conifers like to have the new growth pinched back to create fuller foliage.

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Reducing leaf size in a bonsai tree is essential to proper styling and giving the tree proportion.  Leaf reduction is something that is an art in itself.  Some knowledge of the anatomy of trees helps, as it is very applicable to this aspect of Bonsai. Techniques

Reducing leaf size and the distance between them (the internodes) is the primary focus of the final training of bonsai. This comes after years of developing the trunk, the nebari, and the branches. I have been studying this phenomenon for many years. This is what I have concluded thus far:

Several factors effect the leaf size, as well as the thickness of the branches.  These include:

-The balance between the root mass and the canopy of the bonsai tree,

-Root density as well as the age of the root structure,

-Fertility of the Bonsai Tree,

-Hormone levels of the Bonsai,

Reducing leaf size
Japanese Holly Leaves

-The amount of light your bonsai receives.

These are the main factors that will effect the leaf size of the tree.

Trimming Bonsai – Leaf Reduction is related to the balance between the root mass and the canopy.

Trimming Ficus Bonsai
New growth coming in on my Tiger Bark Ficus
Trimming Bonsai
Trimming the New Growth on a Ficus Bonsai

Balance between the roots and the top growth of the plant must stay balanced.  In the beginning of the growing season the tree will use any stored energy to produce a full canopy of new leaves.  Next the plant will develop shoots for more leafs.  It flips around in the summer when the leafs resupply the roots of the tree with nutrients.  This provides energy to increase top growth.  Roots of the tree will continue to develop until temperature falls below 60 degrees.  At this point the tree will use some of the stored food to increase the root mass but retain reserved energy to start the process over for the next cycle.

In order to effect the growth in your bonsai you need to be familiar with this cycle and all of it’s effects.

One thing you need to avoid is top pruning your bonsai while the tree is dormant.  When you do this you remove buds also known as outlets for receiving food in the growth season.  As a result existing buds are over stimulated, this results in giant leaves.

When you root prune a dormant tree without top pruning, you remove a portion of the food supply used by the tree to stimulate buds and new growth.  As a result buds that are results will produce smaller leaves and shorter nodes.  Just be careful to avoid removing so many roots that water transport is impaired.  If that happens the tree will not be able to support new growth and ultimately will dye.    All about balance.