Defoliating ficus bonsai can be tedious as there are literally thousands of leaves to remove. For a shohin, this could be easily done in half an hour or less but for a large tree, it would take several hours depending on how big and how ramified the tree is. When I prepared the Ficus microcarpa (19′ H x 36″ W) for last year’s 5th US Nationals , it took me 6 hours, spread over two days. But there are short cuts.
This microcarpa measures about 54″ across and is a large tree. I have been working on it for at least 15 years from an imported raw material, basically a cut-down bare-rooted tree with stubby trunks. I have been concentrating on developing branches with good taper. The tree has developed reasonably good secondary and tertiary branch ramifications, and now is the time for finer ramifications to fill out gaps between those branches.
Since it had been growing freely from last defoliation about a year ago, there were a lot of new growths and it looked bushy. I am not going to start cutting off each leaf from such a large tree, it would take me several days! As I am familiar with the tree’s branch structures from previous works, I just treated it like an overgrown bonsai and simply cut off all the branches back to the tree’s silhouette, a quick hatchet job.
This is how it looked after cutting back the excessive growths. Now defoliation looks much more manageable, I then selectively cut the branches where I want to develop finer ramifications. Below is an example of where to cut, indicated by the red lines:
Branches, labeled A, were older growths. They were defoliated perhaps a couple of years ago, from which new buds popped up and grew into smaller twigs, B. Branches A have now served their purposes, they can either be cut off completely to get a Y-branching like the one on the left; or as in the case of the right branches, shortened to encourage back buddings; by removing the strong upper growth, it allows the small branch B to grow and thicken.
This process is repeated for the whole tree. This is how it looks after cutting back branches A and B.
C is the newly formed syconia, ficus’s fruits which should also be removed to direct growth energies to the new buds.
Nearly all the leaves were removed except for a few small inner branches, leaves were left untouched for them to thicken further.
I left the defoliated tree under full sun. My wife and I then happily vacationed for the next two weeks. It thrived and budded very well when we returned. These are the new growths photographed on August 15.
There were profusions of back buddings and new growths. Generally, back buddings and growths occur near the cut tips and along the branches up to about 5″ away from the cuts. By removing the auxin-rich branch tips, back buddings are encouraged but there is a limit as to how far back buds could grow. It is rare to see buds pop up all the way down to the main trunk in a large and mature tree like this.
The following two photos show back buddings in two of larger branches. Buds formed as far down 8-12″ from the cut ends. These buds are good for developing inner branches. My observation is stronger branch tend to bud back further down. There might perhaps be a relationship between the strength of the branch and how much cytokinin is activated for lateral back budding.
Some branches buds later than the others. The right branch in the following photo has three new growths while the left branch is still barren. Upon close examination, there were some tiny green specks indicating some buds will pop up soon, they are somehow suppressed more than the others.
With back budding in full swing, it is time to select which one to keep and which one to remove. This is a photo of the branch I worked on. It is growing almost vertically upwards.
To see which new growths to remove, tilt the branch in the direction where you would wire in the future. It is easier to see which new growths to remove. Keep the new side growths and remove those pointing upwards, downwards or too close to each other. The red lines indicate where the unwanted growths were cut off.
This is after removing the unwanted growths, and energies will be directed to growing and thickening only those branches we want to keep.
Should I Remove the Fertilizer or Not After Defoliation?
That depends on the purpose of the defoliation. If it is to prepare the tree with more uniform and smaller leaves for an upcoming show, then remove the fertilizer and apply light fertilization with fish emulsions when the new leaves have hardened off. If the tree is still under development, I do not remove the fertilizer tea bags. Leaf size may be uneven but growth of the new twigs are benefited by the readily available fertilizer, and with good unobstructed sunlight for photosynthesis after defoliation, they are fed as soon as they emerged. I did not find the young leaves to suffer fertilizer burn even the pot is piled with organic tea bag fertilizer.
Those familiar with summer decandling of Japanese Black Pine to get short needles, the advise is not to fertilize for the first month to keep the needles short. However, ficus is quite a different beast, it has so many latent buds, branches can be severely cut back and they bud back readily. It would be better to continue fertilizing, thicken new growths as fast as possible during developmental stage; when it is time uniform small leaves and fine twigs are needed, one or two more controlled defoliations would do the job.