The following is an extract Jim Smith has written for the book Bonsai Master Class by Craig Coussins, published by Sterling, ISBN-10: 1402735472
Portulacaria afra is described in “Trees of Southern Africa” by Keith Cotes Palgrave published in 1988 by Struik Publishers, Cape Town, as follows.
As yet I have not seen one bloom in Florida; this may be do to the fact that we do not allow our plants to become sufficiently dry.
Portulacaria afra, also called Elephant plant or Small-leaf jade is relatively new in bonsai but one that almost anyone can grow because it is succulent. Since Portulacaria can withstand long periods without water they are excellent plants for beginners. Advanced students of bonsai like them because they adapt to any style and develop relatively fast.
Since Portulacaria is native to South Africa, it will not be possible for most people to find large old specimens to collect but pre-bonsai are available from bonsai dealers that sell tropical plants. When looking at an untrained plant in a nursery it may be difficult for the beginner to visualize a finished bonsai in this tangled mess of branches; but after the unneeded branches are removed you can always find an interesting trunk line.
Portulacaria will tolerate a variety of growing conditions. Like all tropicals it must be protected from long periods of cold temperatures below 40 degrees.
It can be grown outdoors in full sun or indoor if give sufficient light. The plant will develop very fast when given proper care which includes heavy applications of fertilizer. Plants growing outdoors in full sun always need more fertilizer and water than those growing indoors.
When removing branches, all cuts should be flush rather than concave since deep cuts may leave unwanted scars. It is not necessary to seal any of the cuts.
Everyone I have talked to that grows this plant indoors agrees that light is the limiting factor for a healthy plant. They can be successfully grown on windowsills or with artificial light. When growing near a window keep in mind that trees or other buildings nearby may affect the amount of light your plant receives. If you are using florescent grow lights it is important to place the light very close to the bonsai.
Portulacaria does not require any special soil mix; whatever you are using for your other bonsai will probably be satisfactory. Good drainage is always important.
Although the plant is a succulent it is not as particular about over-watering as most other succulents. If the soil you are using drains well you shouldn’t have any problems, always allow the soil to approach dryness before watering.
No special fertilizer is required; any balanced formula will be satisfactory. When repotting I use a slow release fertilizer which can be mixed in the soil, this can be supplemented with liquid 20-20-20 as needed. Since these plants are such fast growers they will need to be fertilized more often than you do with your other bonsai to maintain a dark green foliage.
This plant adapts to any style including cascades and forest plantings. Since it is succulent and most of the water is contained in the trunk and branches.
It is not practical to style the tree with long horizontal branches as they tend to droop because of their weight. This characteristic makes them excellent plants for full cascades.
This plant tolerates drastic pruning if you allow the soil to dry completely before removing large branches and roots.
Refinement is achieved by removing the terminal bud from any branch that you do not wish to grow longer. Since the leaves are opposite and each set of consecutive leaves rotate 90 degrees it is possible to refine the tree by pinching and removing those buds and branches that are not growing where you wish. You can control the direction of growth by pinching back to a set of leaves that are growing in the direction you wish the branch to grow.
When creating shohin we sometimes need to shorten a branch to a vertical set of leaves. In order to get the horizontal growth we need it is necessary to rotate the vertical pair of leaves 90 degrees. A few turns of 1 mm wire at the tip of the branch and a 90 degree twist of the last set of leaves will accomplish this.
Pinching is the key to the refinement of any bonsai; since Portulacaria is fast growing it must be performed on a regular schedule during the growing season. Usually once a week is sufficient for large bonsai, shohin might need pinching twice a week.
It is usually not necessary to defoliate Portulacaria because of the size of their leaves. If you are growing a small shohin and wish to reduce the size of it’s leaves it can be done the same as with other bonsai except that you must allow the soil to become dry before you remove all the leaves. After the leaves have been removed place the plant in a semi-shaded location and do not water it until new growth begins.
Spring is the best time to repot but it can be done at any time if given proper aftercare. It is important that you allow the soil to become dry before repotting or severely pruning the top. Do not water until new growth appears. Keep it in a semi-shaded location until new growth begins, then place it in it’s normal location.
Insects and Disease
I have never had a problem with insects or disease. I learned by accident that the plant would defoliate if sprayed with a petroleum based pesticide. If you find insects on your plant try washing them off with water from your garden hose to control them. If you need insecticides use one that is not petroleum based.
This is one of the easiest plants to reproduce. If any of the trimmings that you remove from your tree are left on the soil they will root in a few weeks. Large cuttings can also be rooted. It is better to allow the cuttings to dry for a day before placing then in the rooting medium. Keep them in a semi-shaded location until rooted.
Large cuttings can be trimmed and shaped into a bonsai style, then rooted in a bonsai pot using your regular bonsai soil for an instant bonsai. Group plantings can also be created this way.