There are two main forms of Japanese Acer: A. japonica and A. Palmatum. Native to east Asia, these plants form a large bush or small tree with soft green, yellow or red lobed leaves.
Family: Sapindaceae (soapberry family)
Botanical Names: Acer palmatum and Acer japonicum
Common Names: Japanese Maple, Moon Maple
Foliage: Deciduous, paired, deeply-lobed leaves. Leaf colour can be green, yellow or red, depending on variety. Most varieties provide excellent autumn leaf colour.
Blossom: Small flowers, often followed by small winged fruits.
Flowering Period: Spring.
Soil: Moist but well-drained soil (sand or loam). Acid or neutral pH. Some varieties will tolerate chalky soil.
Conditions: Sun or partial shade. Planting aspect depends on variety, but most enjoy a shady, sheltered location.
Type: Large shrub or small tree.
Origin: Japan and East Asia
Hardiness: Hardy in the UK.
Japanese maples do best in shelter and shade and prefer an acid soil. Many A. palmatum varieties are suitable for growing in large containers. When using containers it is best to use a general-purpose compost with added John Innes, rather than heavy loam-based types.
Hot dry air, cold wind and late frost can cause leaf scorch (browning at the edges). To avoid this plant in a position that is not affected by cold winds and in an area that does not get morning sun following a frosty night.
Acers cope with partial shade but the foliage colours up best in sunshine.
Water well, especially when grown in containers. Mulch in autumn to protect the shallow roots.
Acers can be pruned very lightly in late autumn and winter, when the trees are dormant. Remove any dead or crossing branches and prune to maintain an attractive shape and structure.
Can be affected by Acer gall mite, aphids, caterpillars and horse chestnut scale. Prone to Verticillium wilt, Acer leaf scorch and honey fungus.
Increase from semi-hardwood cuttings, grafting or by layering.
There are a great many varieties, usually with pale green, crimson or bronze finely-lobed leaves. Average height 10-20ft, spread 15-25ft.
For other maple species see Acers.
Acer palmatum is a deciduous small maple that is relatively slow growing and shade tolerant. Native to damp, shady forests of Asia, this species is highly variable and has been cultivated by Japanese gardeners for hundreds of years. Over 1000 varieties are available, including:
Acer japonicum (full moon maple) is a bushy, slow growing species with lobed, palmate, green leaves that turn rich crimson in autumn. It prefers a moist, semi-shaded, sheltered position. Varieties include: