How to defoliate a bonsai

From BonsaiWIKI

Defoliation is a process of removing some (partial defoliation) or all (total defoliation)of the foliage from a tree. It's usually carried out on broadleaf deciduous trees after the leaves harden off in late spring or early summer. Some trees might be defoliated twice a year.

The benefits of defoliation include the following:

1. Balance the energy throughout the tree by removing foliage where the tree is strongest. The remaining, weaker, leaves will strengthen some, and the strong areas will weaken some, creating a net balance in strength.
2. Reduce the size of leaves. Because the tree's leaves grow back less vigorously than the first flush of growth the replacement leaves will be smaller
3. Improve the penetration of light and air to interior branches. This will improve the health of these weak areas and promote the growth and activity of interior buds (budding back.)
4. Improve ramification by creating more delicate growth and promoting re-growth. When you defoliate the tree will be forced to refoliate itself and will create a "second spring" effect.

Trees that are commonly defoliated

Trees that commonly undergo defoliation include broadleaf deciduous trees like Japanese Maple and Trident Maple. Some people defoliate other types of trees, like Ginkgo, but you should experiment first. Needle conifers are not normally defoliated by the means described above. Pines are instead subject to processes like candle pruning and needle plucking to control growth.

How to Defoliate

1. Trees to be defoliated should be in the peak of health
2. Timing is everything. The new foliage should be given time to "harden off" before defoliating. Defoliation will weaken the tree, so if you have any reason to doubt the timing or the strength of the tree, don't do it.
3. Some species, like Beech or Hornbeam are weaker than others that grow more vigorously and are more resilient - like Trident Maple. Take this into account.
4. You may be removed by plucking leaves individually with the fingertips or cutting them off with a pair of small scissors or a leaf trimmer, a tool shaped like a thread cutter.
5. Some people like to leave a bit of the leaf stem (petiole) attached because they believe this is less likely to cause damage to buds at the base of the leaf that is removed.
6. Remove all of the strong exterior leaves. Leave the weaker interior leaves.

Aftercare

1. Unless it is hot and there is danger of sunburn, you can leave your trees exposed as they were after defoliation.
2. Water consumption is likely to decrease due to the loss in transpiring surface area, but watch out for drying of the soil surface, which is now more exposed to light and wind
3. Refoliation should occur within one month. You can expect the regrowth to be smaller and the internodes (distance between growth points will be reduced.
4. Now is a great time to photograph your tree and double check the wiring. In a few weeks it will be hard to see the structure and the potential for scarring through wire marks is increased.