Aerial roots and growth

Aerial roots are one of the most unique and wonderful features of figs. Aerial roots start out as small fine filaments from the trunk or branches and grow down to the soil. Once rooted into the soil they thicken and can become as thick or thicker than the trunk or branch from which they originated.

Growth of the aerial is faster than growth of the trunk. Designs utilizing aerials may need to be adjusted over time to compensate for the aerials growth.

Ficus virens with aerial on the left side of the trunk, 2016

Ficus virens with aerial on the left side of the trunk, 2016

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The same aerial on the left side of the trunk, 2013.

Ficus virens/infectoria

Seed grown and kept close together these trees are now fused at the base. I think this might be called a clump style.

Ficus virens is the species but in some areas it is called infectoria.

Leaves removed to show the nice branch structure that is developing.

2009, Several seedlings have fused together by being kept in a small container

2009, Several seedlings have fused together by being kept in a small container

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2016, defoliated to show the nice branching that is developing

Ficus burtt-davyi cutting after 5 years

Ficus burtt-davyi is a very useful plant for bonsai. It can form nice bonsai in even small size due to its leaves that can become quite small under proper cultivation. There are also several clones that vary from normal to very small leaves.

The photos below show a larger BD fig that was cut into pieces and the one circled in red is a very small piece that was potted up.

The last shot shows the small tree after about 5 years of growth.

 

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Original mother tree cut into several pieces.

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The pieces potted up individually, 2011

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The same plant in 2016

Some recent bonsai work

Spending a few hours in the growing room and changed and updated a few of my figs.

  1. Ficus natalensis grown from a root cutting. Aluminum foil was used to protect the new root cutting from dehydration. Soon it will be removed.
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    Root cutting taken a few months back

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    Trunk shape achieved with wiring. Next step to form the branches and canopy to suit the trunk shape

     

     

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    Ficus virens has grown out of shape and needs a haircut

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    Ficus virens after trimming

How to thicken a branch

On this bonsai Ficus natalensis the lowest branch on the right side is not thick enough. Most often the lowest branch should be the thickest on the tree. In order to achieve proper thickness the branch is allowed to grow longer than the style dictates. Note the leaves are also larger than the rest of the tree which is being trimmed regularly.

In a year or two the branch will thicken because of its continued growth and then it will be appropriately shortened. The next step will be to continue the process of shaping the branch properly.

The area in red is allowed to grow without trimming to thicken the branch

The area in red is allowed to grow without trimming to thicken the branch

Slave branches

Slave branches are used to thicken a part of the trunk or branch that needs to be heavier. Slave branches are allowed to grow wildly without trimming and when the thickening has been achieved they are removed.

This Ficus natalensis has a slim trunk that would be improved by thickening it to introduce some more taper. The branch outlined in red was allowed to grow for a year or two to thicken the trunk.

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Slave branch on this Ficus natalensis to thicken the lower trunk of the tree

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Lower trunk has been thickened sufficiently so the slave branch has been removed

 

Aerial roots

This clump of Ficus virens/infectoria is seed grown and by being kept in a small container the individual trees now are fused and live on a common root system and lower trunk.

Of interest is the somewhat peculiar formation seen in the red outline. It is an aerial root that has existed for quite a few years. The aerial initially formed as a small thread-like structure but because the ambient humidity is low it has never reached the soil to form a pillar trunk. Each year when humidity is high new aerials try to sprout from it  but as the high humidity is only temporary the aerials never succeed in elongating and reaching to the ground. It gets thicker each year and the “ball” is enlarging year by year.

The appearance now is of a solid wood ball on which spikes that are aborted aerials jut out. Perhaps one day I will cut it off and see if I can root it as a cutting.

Ficus virens/infectoria showing the aborted aerial root growing off the trunk

Ficus virens/infectoria showing the aborted aerial root growing off the trunk

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Closer view of the aerial and the spikes growing from it

 

 


The definitive reference work on Ficus
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Creating a bonsai from a cutting

Taking cuttings is one of the best ways to start a bonsai tree. In this example a cutting of Ficus ‘Mystery’ was taken. It was a long straight piece of stem with several aerial roots. A cutting taken with aerial roots is almost guaranteed to root.

In this case the cutting rooted successfully and several years later the bonsai created was an attractive semi-cascade tree.

I take cuttings regularly and place them in bonsai soil and enclose the pot and cutting in a plastic bag to keep the humidity high. The bag is kept out of direct sunlight but in good bright light. Open the bat and water the soil as needed to keep the soil from getting dry but do not keep the soil totally full of water.

The bonsai created from section 4 of the photograph

The bonsai created from section 4 of the photograph below

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Section 4 with its aerial roots was taken as a cutting

 

Starting with less than wonderful material

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2011, at the start not looking too promising

This is a pretty typical plant. Ficus rubiginosa, that one can purchase in a nursery. It has had little or no training and seems unlikely to develop into a bonsai tree.

First step a chop to reduce the height

First step a chop to reduce the height

Allowing growth

Allowing growth

More growth, some trimming to shape

More growth, some trimming to shape, and wiring

2016, partially defoliated to encourage more twigging

2016, partially defoliated to encourage more twigging  

At last one begin to see the potential bonsai emerging from its rather humble beginnings.

Root-over-rock style

Ficus microcarpa placed on this rock about 12 years ago

Collected Ficus microcarpa placed on this rock about 12 years ago

Figs grow very well when placed on or grown over a rock. Root-over-rock designs are also very much admired by bonsai lovers.

Figs with their aggressive root systems easily tolerate being placed over a rock. The rock is covered with soil and the tree is allowed to grow vigorously to attach the roots to the rock. The soil is gradually removed over time to reveal the roots.

This Ficus microcarpa tree was collected with my bonsai friend David Fukumoto about 12 years ago and placed on the rock, roots initially covered by aluminum foil to protect the new roots. Over time the foil was removed and the roots were now air adapted.