Why Do I Repot a Big Ficus From a Ceramic Pot into a Wooden Box?

This Ficus microcarpa was potted into a 24″ round ceramic pot in 2015. By 2018, it needed repotting again but I procrastinated and did not do it in 2019 either. I finally repotted it a few days ago, but into a wooden box.  I jokingly said it was because I needed to reduce the overall weight. That is true but there are more important horticultural reasons repotting it into a wooden box, like rejuvenating the roots, regaining the tree’s health, and working on the overgrown aerial roots and nebari.

Potted into a 24″ round ceramic pot, May 2015.

July, 2018. Ready for a repot but did not do it.

Why Use a Wooden Box?

To restore a bonsai’s health, it is a good idea to repot the tree into a slightly larger container, preferably in a terra cotta pot, a wooden box or a Styrofoam box.  A slightly larger container provides more soil volume and extra rooms for the roots to rejuvenate, increased surface areas between soil aggregates also allow the roots to breath better and grow more fibrous roots.  A cedar picket fence wooden box is an obvious choice since I cannot find a larger terra cotta pot or a big Styrofoam box. Although the latter can protect the roots from over heating during our intense summer heat, it is too glaring and stands out too much among the other trees, unless I could paint it.

As for weight, the 24″ ceramic pot weighed 32 lb., a comparable wooden box weighed about 5 lb.  I made a rough calculation, this round pot with tapered wall has a volume of about 1,100 cubic inches (about 18 L.), a square box holds almost twice the amount of soil.  Your tree will thank you for the extra room while in recovery.

Reworking Overgrown or Thickened roots

Aerial roots are great for improving the tree’s nebari, but they can become too big, crisscrossed or grew in unintended direction if one is not diligent in controlling and incorporating them to the intended design.

These two photos show how the skinny grafted aerial roots grew in 4 years without repotting in between:

Grafted aerial roots A, B and C in 2015 and 2019. Branch D was removed as it was sticking too much towards the front.

These grafted roots needed repositioning and incorporating into the nebari:

Repositioning thicker roots using aluminum wires and tourniquet.

Crossed roots repositioned, once fused, the top sections will be cut off.

Exposing More of the Nebari

Every time I repotted, I raised and exposed the nebari by about 1/2”. This time I raised it by about an inch. Exposing it gave the tree a larger nebari in each repot.

Root base raised by about an inch, shown by differences in tree bark colors.

Another advantage of using a wooden box is I could easily put in a few screws on the box to attach guy wires to bring down branches.

Two “Root-On-Wall” Ficus Penjing – How I Create This New Style

This article was written by Mr. Xuenian Han (韩学年), a well-known Lingnan penjing master. It was published in Mr. Shaohong Liu’s (刘少红) “The World of Penjing” (盆景世界), the most widely read online penjing magazine in China with over 135,000 subscribed readers. Both Mr. Han and Mr. Liu gave me permissions to translate this article and share it with English readers on how this new style was developed.

“The Fittest”, a “root-on-wall” ficus created by Mr. Xuenian Han. 韩学年作品《适者》（附壁榕）

Ficus microcarpa is a native tree species in the Lingnan region. As a fast growing tree and an ability to grow in a broad range of habitats, it is widely cultivated in urban and rural areas. In the Pearl River Delta, especially in villages and towns along the river, banyan trees with broad canopies provide shades and are popular with villagers, where they could gather and cool themselves during the hot summer days.

Ficus has large, powerful tree trunk and wide spreading, old gnarly roots. Since Lingnan penjing practitioners often model their trees based on close-range observations of how trees grow in nature, thus, the Banyan style was born. Ficus is a popular species for Lingnan penjing, whether the material is field grown or collected, key banyan features are artistically recreated and portrayed in a grow pot. There are many excellent examples of banyan style penjing.

Ficus growing on the old Nanfeng kiln wall in Foshan city, Guangdong. 佛山市“南风古灶”古榕

Ficus have aerial roots, when these roots touch and anchor themselves onto the ground the tree would continue to grow outwards, creating a forest-like image even though it is just a single tree; and this is the familiar banyan image.  Since ficus is a strong survivor and adapts to myriads of environments, there is another tree form from which these two “root-on-wall” penjing were based upon, and I will discuss how I created them.

An old ficus growing along a river in Shunde, Guandong. 本地（顺德）一河边古榕

How Did Tiger Bark, Kinmen, Golden Gate Ficus Get Their Names?

Ficus microcarpa, commonly called the Chinese Banyan or Indian Laurel, is the most used ficus species for bonsai.  Although it has many cultivars and varieties, Tiger Bark, aka Golden Gate, Kinmen, Kingman, Kimeng, Kin Men etc. is perhaps the most popular because it is easy to grow, has a beautiful bark, and their leaves reduced easily.  Where do these names come from?

My ‘Tiger Bark’ ficus which won the Best Tropical Bonsai in the 2016 US National Bonsai Exhibitions.  The history of its training from a pre-bonsai was described in an older blog.

Min Hsuan Lo gave a short description on the discovery and naming of Kinmen (Tiger Bark) ficus in his book, “Bonsai Journey”.  Since it was written in Chinese and not many ficus enthusiasts in the West read Chinese, I will retell the story with explanations on related Taiwan history and background.

This cultivar was discovered in the 1970s by a grower in southern part of Taiwan, and was named after the grower’s nickname, “Kim M’ng”, which means blond or golden hair in Taiwanese dialect for his blond hair.  I do not know whether he is a natural blond or not; the Dutch colonized southern Taiwan from 1622 to 1644 until they were driven out by the Ming General, Chen Cheng Kong.  To this day, blond hair occasionally show up in family members of mixed Dutch and local descendents.

Defoliating Ficus Bonsai

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.

Let Your Ficus Grow Before Repotting and Defoliation

Summer is a busy time for people who love and grow a lot of sub-tropical and tropical bonsai. I live in Southeast Texas, and start to repot, defoliate and wire my ficus in June. By this time the Texas heat is intense, daily temperature is in the 90s with heat index over 100ºF; it is very hot working outside even under the shade. I repot my ficus later than what most people living in Zone 9 would do because I want my trees to take advantage of spring growth spurt before doing any major maintenance work. You may have read advises such as repot tropical trees when the night temperature is above 60ºF. That is correct for safety reason but it does not mean you have to plunge right into it when the weather warms up. Just take it easy and let your tree grow, let them become healthy and strong before repotting and defoliation.

Our last frost date is around third week of March. In early April I moved my ficus out of the greenhouse and let them sit under full sun in open air. Ficus grows virtually year round for us, when over wintering in greenhouse they just slowed down their growth, hardly noticeable but definitely continue to grow. That’s why I do not remove my fertilizer in winter. Once outside, with plenty of sunshine, fertilizer and water, there is a sudden surge in new growths. I let them have about 2 months of growth to gain vigors before starting any work.

The ficus are in open space on the south east side of the yard. Full sun till around 2 p.m. when the oak tree which is about 40 feet away begins to block the afternoon sun and casts some shadows.

I put my fertilizer in tea bags and placed them on top of the soil surface. A lot of new roots grow underneath the tea bags, and some may even grow into it. I move the tea bags around every few weeks.