Black olive bonsai are not created from “black olives.” They are also not related to the Mediterranean olive. Scientifically speaking, the tree is the Bucida species. The smallest leaves are on theBucida spinosa.
The reason for its common name is questionable. The plant has insignificant flowers, tiny seeds - no fruit. Some suggest the seeds have an olive shape. Because of its growth pattern, another common name . . . "the geometry tree" is much easier to understand how it came about.
In the "old days" of South Florida bonsai, wild dwarf black olive trees were frequently gathered from the shorelines of the Bahamas. Today, Bucida spinosa in its native habitats (including the Bahamas, Puerto Rico and Cuba) is illegal to collect!
Although they can be grown from seed, today, nursery plants are the most frequently used bonsai starter plants.
The natural features of this tropical make it an especially desirable subject ... small leaves, zig-zag branches and as it ages, deep fissured, textured bark. Unfortunately, the branches are opposite and spiral. This form presents some challenges.
The best asset of this plant is the branches themselves have alternating branchlets.
Because of this wonderful alternating trait, side branches are often wired and raised as tops to create classic shapes.
As young plants the trunk and branches are very flexible. They can be shaped into almost any style.
The most difficult part of styling this plant as bonsai is making the decision to cut off shapely, exotic branches.
Remember, if a branch doesn't work in the design, it has to go!
The sad part? The beautiful cuttings very rarely root. Bucida are primarily grown from seed and tiny tip cuttings. Air layers take a very long time.
For larger bonsai, Bucida buceras, Bucida shady lady and other larger leaf variations should be considered. (The leaves are still small.) In some ways they are easier to maintain than B. spinosa. They don't drop leaves as freely and are quicker to re-establish when root pruned. They are also known to grow indoors more easily than small leaf varieties.
One of the primary killers of black olive trees is a rush to pot at the wrong time of year. In the tropics most people wait until May or June to root prune and repot Bucida. The key to timing is longer days and warm nights.
Severe root pruning in late summer (even though the nights may still be warm) is also risky. Late in the season your black olive bonsai may not have enough time to regenerate new roots before the shorter days and cooler nights arrive.
Check the roots annually. In warm climates yearly root pruning is
common; however in other climates probably every other year will be
adequate. It is better to trim when needed than to wait and have to do a
major root pruning.
The true olive - Olea Europa - the one with real olives - was brought to California by the Spanish in the mid 1800s. It is also a good bonsai subject. The two trees are in no way related and require very different care.