General Information:
One of the most loved species of cultivated Bonsai, the Chinese Olive – Olea sp. – has a rich historical and mythical lore. Its deep green leaves have a grayish underside and it produces yellow-ish white flowers followed by green or black fruit in late summer or early fall. The Chinese Olive is tolerant of wind (both hot and cold), soil conditions, and elevation (can live at altitudes up to 4,900 feet.) Creating your own jin/shari is not a good idea as the bark cracks easily leaving the tree exposed to fungal infestation. The Chinese Olive can live 800 to 1,000 years and its trunk takes on an aged, stony appearance when old.
Location:
Chinese Olive trees like full sun in the summer, less in winter, but still full light as an indoor plant. Leaves can withstand temperatures down to 43º F but the roots dislike freezing temperatures. The Chinese Olive tree should be kept below 64º F in winter.
Watering:
Bonsai trees live in small pots and their world dries out much quicker than plants in the ground or in bigger pots, so close attention should be paid to watering. Check and water your bonsai frequently. Striking a balance between not enough water and too much water can be a bit tricky but is very important. Water thoroughly, keeping it damp but not wet. Reduce watering in the winter. An old bonsai watering trick is to place the entire pot in a sink of water an inch or two deep and let the water absorb from the holes in the bottom of the pot. The Chinese Olive tree may benefit from weekly misting.
An inexpensive moisture meter takes the guesswork out of watering. We sell them on our web-site. Water slowly so it absorbs into the dirt, otherwise the water will run all over your table. We pot our bonsai trees specifically to drain well, so it’s almost impossible to over water.
Fertilizing:
Fertilizing a bonsai is essential to its health because the nutrients in the soil leave very quickly with the water. When new growth appears in the spring, it’s time to start feeding your bonsai. Use a liquid bonsai fertilizer or half-strength general purpose plant food every two weeks from spring to autumn. Do not fertilize for three months after repotting. The Chinese Olive tree can benefit from an addition of pulverized organic fertilizer in mid-spring.
Pruning:
To develop the foliage, pinch out the tender new, usually green, shoots using your fingers cutting to first or third couple of leaves. Chinese Olives don’t produce new shoots around the cut when you prune a branch. If you want new shoots, allow them to mature to a branch length longer than you eventually want it to be and then shorten it later. Creating your own jin/shari is not a good idea as the bark cracks easily leaving the tree exposed to fungal infestation. There may be some natural die-back which may affect the design of the tree.
Wiring:
Use the thinnest training wire that will hold the branch in the desired position. DO NOT WIRE A BONSAI JUST AFTER REPOTTING. Wind the training wire in the direction the branch is bent in order to keep the wire from loosening. Wrapping the wire too tightly will cause scarring. Begin at the base of the Bonsai tree and slowly wrap the wire around the trunk to anchor. Continue along the branch you wish to train. Repeat the process as needed.
One author writes it is best not to wire Chinese Olive trees. He says the branches are so brittle that there is little point in even trying to train them. Branch shape can be achieved by pruning alone.
Wiring must be watched carefully for signs of wire cutting into the bark. Wire must be removed immediately if this happens. If necessary, the tree can be re-wired after removing the old wire.
Repotting:
Reduce the roots gradually, removing no more than one third of the root ball at each repotting. Remove a proportional number of old leaves. If more drastic root pruning is needed, complete defoliation is advised. Retain about 50 percent of the fine roots. Repot in fast-draining bonsai soil, slightly calciferous (with a high sand and lime content.)
Repot Chinese Olive trees in late winter remembering to prune roots only moderately. Generally, repot every 3 to 4 years.
Insects and Diseases:
Aphids, ants, black mold, scale, and bark borer occasionally bother
Chinese Olive trees. Eryphide mites cause galls but no control is needed. Insecticides such as Diazinon and Permethrin will kill the tree. We recommend Orthenex or an insecticide with Acephate, Resmethrin, or Triforine always using the weakest insecticide possible that will address a particular problem. We recommend spraying your Chinese Olive tree every few months with a non-toxic insect spray, but DO NOT SPRAY WHEN SOIL IS DRY.
Scale is usually identified by brown or black bumps on the branches. These bumps contain insects under a protective waxy shell. A very sticky secretion that discolors the branches may also be present.
Chinese Olive trees are also susceptible to mold problems which are more likely during the dreary, wet fall and winter days and into soggy spring days. Use a mild fungicide and keep the air flowing to chase away mold problems.
DISCLAIMER: The content provided in this article is not warranted or guaranteed by Bonsai Outlet. The content provided is intended for entertainment and/or educational purposes in order to introduce to the reader key ideas, concepts, and/or product reviews. We are not liable for any negative consequences that may result from implementing any information covered in our articles or tutorials. Happy bonsai gardening.
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