Texas Ebony, TE, is an excellent indoor bonsai material that forms a graceful, airy and attractive tree. It is also extremely tolerant of growing conditions in the home.
Pithecellobium flexicaule is the old scientific name for the Texas Ebony but it has been re-classified as Ebenopsis ebano in the Fabaceae or Legume family. Fortunately we can still call it by its common name, Texas Ebony.
The tree can form a 25-30 foot tall tree with a four feet trunk diameter! The size this tree attains in the ground is in sharp contrast to the small specimens that we find grown for indoor bonsai. In nature it is also forms multi-stemmed shrub-like plants.
The TE is native to Texas and Mexico. It is found in areas that get extremely dry and hot and so it has evolved strategies to deal with these stresses. Its surival strategy is to go dormant and lose all its leaves during dry spells. Still, it is also able to grow in areas with significantly more moisture.
The wood is said to be useful for furniture and the seeds used as a coffee substitute.
The compound leaves of the TE are composed of many small leaflets. The whole leaf is about two inches long, with the individual leaflets being much smaller. The leaves are not the smallest compound leaf of any indoor bonsai material. The Divi Divi, Caesalpina coriaria, another legume used for bonsai has a finer, smaller compound leaf. Still, the leaves of TE are small enough that even tiny bonsai can be created.
The tree is reluctant to bloom indoors except under very high light situations. The flower is a typical legume flower of white to yellow.
Growth on the branches is always zig-zag.
The bark is grey-brown in color with some fissures and roughness on the older trunk areas.
The TE often has multiple layers of roots. The best layer of roots can be retained to form a nice radial root pattern and the others removed. Elevated or air roots can be removed if a better lower root line exists.
There has been discussion on the internet bonsai interest groups about a prominent, one sided, or tap root that seems to be present on many TE trees. Carl Rosner handled his tree’s tap root by drilling holes around the trunk below the soil level, treating with hormone powder and then wrapping with sphagnum moss. At the next potting new roots had formed and the tap root was shortened below the new root line.
The wood of the Texas Ebony is quite hard and resistant. It can be used for jin or deadwood designs. If the deadwood is kept dry and lime sulfured it will last for years.
Branches over 1/2 inch thick will not bend. It is easier to wire or bend branches while they are still green.
The TE may be grown in almost any soil. A mix of screened particles containing 50% inorganic and 50% organics is a good starting mix. If you tend to over-water trees then use a nearly inorganic mix such as red lava, chicken grit, decomposed granite, akadama, or even properly sized gravel. Make sure to screen out all fine particles that fall through a window screen and only use the material that stays on top of the screen.
In nature this plant tolerates soil dryness but it is intolerant of constantly wet feet. Great care must be taken after repotting and root pruning since injured roots can rot if kept constantly wet. If the tree is allowed to go bone dry, it will lose all its leaves and then replace them when conditions improve. Losing leaves stresses the tree, so water the soil as with all bonsai, allow it to get nearly dry before watering it again.
In nature TE will tolerate temperatures to the low teens. As a bonsai Texas Ebony tolerates normal room temperatures, but if it is kept in a container do not let it freeze. A mild frost will not damage the tree but it will lose its leaves and go into a period of dormancy. If the tree is kept at normal room temperatures, and watered properly it will not leaf drop and stays evergreen.
In the home TE tolerates humid or dry air.
The Texas Ebony grows best in bright light or even full sun. It can be maintained in low or indirect window light but the growth of the tree under those conditions is extremely slow. Supplementation of window light with a fluorescent bulb placed at 4 inches above the leaves or a spotlight directing light onto the tree will be of great help in getting more growth.
As with many legumes the leaves fold up at night, or with transplanting.
The tree is happy with any fertilizer. A good plan is to fertilize each week when the tree is in active growth. Use a fertilizer solution at half the recommended strength and fertilize only after watering the tree. As a legume the tree has the ability, assisted by soil bacteria, to extract nitrogen from the air and use it for growth.
There are usually no insects that plague Texas Ebony but occasionally trees can be attacked by scale. Dormant or horticultural oil can be used at 1 tablespoon per gallon of water. Make sure to spray all the leaves and branches on both the upper and lower surfaces each week for four weeks. This should eliminate the scale.
Indoors, the tree grows quite slowly so repotting will only be needed every two to three years.
Large reduction cuts made on the branches and trunk will sprout new growth from latent buds. Reductions or “hacking back” a larger tree to a much shorter tree may be a problem in that the new growth may not break back near the cut. TE often sprouts much lower than the reduction cut; so leave a length of trunk 50% longer than you think the eventual trunk might need to be. Over time, reduce the extra length back to the desired lower apex after the tree sprouts back.
Texas Ebony’s only drawback is the wicked spines hidden in the foliage. The spines are a major nuisance when bending or wiring branches. Use gloves or better yet cut all the spines off with bonsai cutters or nail clippers.
Under indoor conditions the trunk thickens very slowly, so buy or collect as large a trunk as you desire. Unless you are a teenager you will likely not live long enough to grow a seed to a large bonsai indoors.
Due to its zig-zag growth, wiring is not necessary and the tree can be shaped with clip-and-grow techniques. Wire should be applied while the branches are green or just turning woody. Older and heavier branches are quite stiff and difficult to wire.
The TE can be used for styles that are light, airy and graceful. Styles needing thick, powerful trunks are much harder to accomplish.
Group plantings work very well utilizing the graceful and slender trunks.
TE is easy to grow from cuttings.
Use cuttings of slightly woody, hardened-off green branches.
Large woody pieces are harder to root and may rot before rooting.
A rooting hormone may increase the rooting success.
TE seed is contained in a pod containing several large brown beans each covered with a waxy, hard coat. This coat must be softened before the seed can sprout. Seed may be planted into bonsai soil, covered and kept moist. The seed will sprout in several weeks to a month. Faster sprouting can be achieved by pouring boiling water over the seed, allowing it to cool overnight and then planting the seed. Alternatively, a pin can be used to penetrate the thick covering. Seed treated in this way will sprout in a week or less.
Often much of the collected seed will not be viable due to an insect larvae that lives in and eats the seeds.
The Texas Ebony is a great indoor material that should be part of every indoor bonsai collection. Obtain as large a trunk as you desire since trunk growth is very slow.