Common Name: Japanese maple
Type: Deciduous shrub
Family: Sapindaceae
Zone: 5 to 9
Height: 6.00 to 9.00 feet
Spread: 8.00 to 12.00 feet
Bloom Time: April
Bloom Description: Reddish-purple
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. Avoid hot and dry sites. Site in locations protected from strong winds. 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 to 7 but less frequently 9 toothed lobes. Small reddish-purple flowers in umbels bloom in spring (April) followed by winged samaras in pairs which ripen in September-October. Fall color includes an often spectacular combination of shades of yellow, red, purple and bronze.
Var. dissectum is typically a much smaller, rounded, slow-growing shrubby form (often with cascading branching) that rarely matures to more than 12' tall with a larger spread. Palmate leaves, each having 7-11 deeply incised lobes, are deeply cut to the base of the leaf. These dissected-leaf shrubs are commonly called laceleaf Japanese maple, cutleaf Japanese maple or threadleaf Japanese maple. Dissectum means deeply cut in reference to the deeply cut, feathery nature of the leaves.
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.
'Garnet' is a dissected form that typically matures over time in an upright-pendulous mound to 6-9' tall. Deeply cut, 7-lobed leaves emerge red-orange (color of the garnet gemstone) in spring with good color retention until mid summer before fading to purplish-green. Foliage turns red in fall.
Problems
Potential disease problems include stem canker, leaf spots, fusarium, verticillium wilt, botrytis, anthracnose and root rots. Potential insect pests include aphids, scale, borers 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
Dissected forms of Japanese maples are generally grown for their attractive foliage and low-spreading shape. Specimen/accent or group around the home or yard or patio or periphery of the border or rock garden. Good sun-dappled understory plant. Dissected foliage and cascading form can be showcased by planting his cultivar near a pond or water garden. Smaller plants can be effective in containers.