The Chinese Elm, also known as Ulmus Parvifolia or Ulmus Chinensis, is native to China, Korea, and Japan. It is a fast-growing tree which proved highly resistant to the Dutch elm disease which wiped out majority of the Elms. The tree can be evergreen or deciduous and can grow up to height of 40 to 50 feet, while in its native areas of East Asia, it can grow up to 60 feet. The tree usually has a rounded canopy with drooping branches and thus makes for an excellent landscaping tree, and can usually be found along streets and in parks.
The species is adaptable to a variety of soils and weather conditions. It has a thin, mottled brown bark, quite distinctive from the other elms. It is usually confused with a Zelkova tree, however one can easily make out the difference by proper leaf identification. The leaves of the tree are small and shiny, with even sized teeth.
Due to its adaptability and fast growth, it is considered as an excellent choice for bonsai. It is an ideal choice for beginners as it is not over-sensitive to things like over-watering, under-watering, or changes in temperature.
How to care for an Ulmus Bonsai
The Chinese Elm can be plotted from the cutting taken from the established plants. Once acquired, the cutting should be kept in water for a few days for roots to develop. Post that, it should be planted with a mixture loam, peat moss, and sand.
The bonsai Ulmus grows well indoor as well as outdoors. It should be kept in full sun or partial shade. The bonsai grows best in a temperature ranging between 60 and 70 degrees Fahrenheit. The tree is not highly sensitive to cold and usually frost-hardy. A free-draining soil with organic components works best for the Chinese elm.
The soil should never be allowed to get completely dry as the elm prefers some moisture, however over-watering must be avoided. Instead of watering as a routine, it should be watered as when required. It should be watered thoroughly and then left until the top soil feels slightly dry.
Since it’s a fast growing tree, the Ulmus requires regular supply of nutrients and should be fertilized bi-weekly during growing season and monthly during winter. However, it doesn’t require fast-acting fertilizers and a balanced organic feed works well.
A young Ulmus should be repotted every year, and ever 2-3 years once it gets a little old. Since, it is a fast growing tree with a vigorous root-system, it needs such frequent repotting initially. Spring is the best season for repotting.
The leaves can be pruned frequently and round the year. The shoots should be allowed to extend 3 or 4 nodes and then be pruned back to 1 or 2 leaves. The tree responds well to pruning and the leaf size decreases gradually. Roots should be pruned well before repotting.
Since the bark is soft, the tree should not be wired for prolonged periods as it may leave marks. However, it could be wired during growing season for effective shaping.
The Chinese Elm is highly resistant to the Dutch Elm disease and in a bonsai form it is not usually prone to the disease. However, the tree must be protected from Aphids and gall mites using insecticides and pesticides.
Unlike other elms, the Chinese Elm is easier to maintain and grow. With effective care and dedication, the ulmus bonsai can be grown and maintained for generations.