Common Name: Japanese maple
Type: Tree
Family: Sapindaceae
Zone: 5 to 9
Height: 15.00 to 20.00 feet
Spread: 10.00 to 15.00 feet
Bloom Time: April
Bloom Description: Red
Sun: Full sun to part shade
Water: Medium
Maintenance: Low
Flower: Insignificant
Leaf: Colorful, Good Fall
Tolerate: Rabbit, Black Walnut
Culture
Best grown in moist, organically rich, slightly acidic, well-drained soils in full sun to part shade. Grows well in sandy loams. May be grown in full sun in the northern parts of its growing range, but prefers some part afternoon shade in the southern parts (including St. Louis) of its growing range. New foliage may scorch in full sun locations in hot summers areas, particularly if soils are not kept consistently moist. Mulch helps retain soil moisture and keep roots cool. Site in locations protected from strong winds. Avoid hot and dry sites. Fertilize in spring before leaves emerge. Pruning is best kept to a minimum, but if needed should be done in late fall to mid winter. Spring or summer pruning often results in significant bleeding.
Noteworthy Characteristics
Acer palmatum, commonly called Japanese maple, is a deciduous shrub or small tree that typically grows to 10-25' (infrequently to 40') tall. It is native to Japan, Korea and China. General plant form is rounded to broad-rounded, often with low branching. Each palmate green leaf (2-5" long) has 5 or 7 but less frequently 9 pointed toothed lobes. Small reddish-purple flowers in umbels bloom in mid spring (April). The flowers are rather attractive close up, but are not particularly showy from a distance. Flowers are followed by samaras (to 3/4" long) in pairs. Samaras ripen in September-October. Fall color includes shades of yellow, red-purple and bronze. Cultivars (often grafted) are quite variable.
Genus name is the Latin name for a maple tree.
Specific epithet is in reference to the palmate nature of the leaves. Each leaf has several lobes (typically 5–7) that all originate from one point looking like an open hand with outstretched fingers.
‘Suminagashi' is a broad upright cultivar. Trees are vase-shaped when young, but gradually broaden with age. This is a fast-growing cultivar that typically grows to 8-10' tall over the first ten years, eventually maturing to 15-20' tall and 10-15' wide. Branches may weep at the ends. Palmate leaves (to 4" long) are deeply cut into seven (less frequently 9) elongate-ovate lobes each having toothed margins and pointed tips. Foliage emerges purple red in spring, matures to deep maroon in summer and finally turns bright red in fall. Small reddish flowers in spring are somewhat attractive on close inspection, but are not showy from a distance.
Problems
Potential disease problems include stem canker, leaf spots, fusarium, verticillium wilt, botrytis, anthracnose and root rots. Potential insect pests include aphids, scale, borers, bagworms, and root weevils. Mites may be troublesome. Foliage tends to leaf out early in spring and is subject to damage from late spring frosts. Chlorosis may occur in high pH soils.
Uses
Japanese maples are generally grown for their attractive foliage and shape. Specimen/accent or group around the home or yard or periphery of the border. Good sun-dappled understory tree. Woodland garden margins. Screen. Bonsai.