Chinese elm is fast growing, deciduous or evergreen depending on its location, forms a graceful upright rounded canopy with shiny, dark green leathery leaves. Elm is moderately salt tolerant. Several dwarf varieties, sports of Ulmus parvifolia, exist which grow slower than the ordinary Chinese elm but it produces a much finer network of twigs and branches. It is these sports which are used for bonsai.
Will grow in full sun or partial shade.
Zones 5B – 10A. More restricted zones may apply to some of the dwarf varieties.
Needs a lot of water.
To retain and produce small leaves, do not feed high nitrogen fast-acting fertilizers. Feeding three times a year is sufficient to maintain good colour and healthy growth without enlarging the size of the leaves.
Pruning and wiring:
Most shaping can be done by pruning. The bark is thin and may be damaged easily.
Because these dwarf varieties are sports of another plant, they can only be propagated by cutting or layering. Cuttings may be made from new tip growth taken in early summer.
They transplant well. Any type of soil with good drainage seems to grow them well. They have heavy root growth so must have root room.
Pests and diseases:
Borers and chewing insects seem to be the only pests bothering the plant. Cankers may develop on young trunks where soil is excessively wet.
Some species suitable for bonsai:
Ulmus parvifolia, var ‘Catlin’, is a sport of the common Chinese elm. It is partly evergreen in mild climate and evergreen in the south. Its leaves are a 1/4” to 3/4” long and are a shiny dark green, lanceolate and smaller than zelkova. John Catlin, a landscape designer in California, found this sport on an Ulmus parvifolia or Chinese elm in a nursery in about 1953. Jim Barrett named it Catlin Elm to honour the man who found it and to separate it from the Chinese elm.
Ulmus parvifolia ,var ‘Drake’, USDA Hardiness zone 7 to 9. has small, dark green leaves, sweeping, upright branches forming a rounded crown and greater leaf retention being almost evergreen in CA and FL.
Ulmus parvifolia, var ‘Dynasty’, has smooth dark grey bark, smaller leaves and is vase-shaped, with red fall colour in the north.
Ulmus parvifolia, var ‘Frosty’, has a small (.75 inch long) white-margined leaf which may revert back to green.
USDA Fact Sheet ST – 652
Compiled by Thomas L. Zane