Zelkova bonsai is a classic bonsai. The most common shape and bonsai style is a broom or hokidachi in Japanese. The main reason for this is the natural growth habit of the zelkova. With a proper trunk and correct trim of the branches, it will naturally grow in a broom bonsai. The zelkova bonsai is also a good replacement for the Chinese elm since it is less subject to diseases and pests even if it is part of the same ulmaceae family. The two most popular zelkova bonsai species are the following:
† (Japanese Grey Bark elm)
The classic zelkova bonsai because of its rapid and vigorous growth rate, the grey bark elm will grow bright green serrated leaves abundantly. It tolerates heavy trimming and will bounce back with a more vigorous growth. The bark is smooth and pale grey which makes it attractive to bonsai grower. The zelkova serrata is native to Japan and China. A mature tree can reach an height of 100 feetís with a trunk girth of 4 feetís. Leaves are usually 1 to 3 inches in size.
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† (Chinese Zelkova)
This is a smaller version of the zelkova serrata. At mature age it will reach 40 feetís. It is native to china only and is usually found in high altitude area. The bark is more of a brown to grey color and is less attractive then the Japanese grey bark elm.
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Basic Zelkova Bonsai care
The zelkova bonsai tree will need semi-shade to full sun in order to thrive and grow quickly. During the hotter period of summer, tree should be place in semi-shade to avoid the leaves to dry too quickly due to direct sunlight.
Zelkova bonsai do not like too much water. It is best to water in the morning and let the soil dry out till next morning. During the hotter days of summer, it is recommend to spray water on the foliage to keep the tree cool and fresh.
Feeding and Fertilizer
It is recommend not to over fertilize your zelkova bonsai. A balanced chemical fertilizer can be used every other week. If you prefer to fertilize at half-dose, you can fertilize once a week.
Natural fertilizer can be used from spring to fall without any problem.
Zelkova Bonsai techniques
The classic zelkova bonsai technique is to develop a broom style bonsai. This is achieved by chopping a trunk in a V cut. The new shoot should be held upright till they harden in place. Then, you prune back those shoots to the first bud or two leaves set and so on. Leaf size reduction can also be done by two methods. The first being a balanced defoliation and the second is by keeping the roots bound. Defoliation should not be done the same year that you have root trim and repotted your zelkova bonsai. Major structural change should be done in winter to prevent an excessive loss of sap. It is also recommend to shape in winter since you can see the whole silhouette and branch structure.
Zelkova Bonsai pests and diseases
Zelkova bonsai are resistant to pests and no pest as ever been classified as a constant menace to this genus.
An healthy tree will resist to disease such as the dutch elm disease. The key is too avoid weakening the tree with repeated wounds and cuts.
Zelkova bonsai propagation
Zelkova seeds do germinate easily. The germination rate is good. Zelkova Seeds are a cheap and good way to jumpstart a collection.
Cuttings are also possible with the zelkova. Rooting hormones can help the rooting on both soft and hard wood cuttings.
If you have found a good base and branch structure you could air layer a tree to make it into a zelkova bonsai. Since zelkova growth is vigorous, it is easy to root a branch.