Common Name: Japanese alder
Type: Tree
Family: Betulaceae
Native Range: Japan, Korea, Manchuria
Zone: 5 to 7
Height: 40.00 to 60.00 feet
Spread: 30.00 to 50.00 feet
Bloom Time: March
Bloom Description: Yellow-brown (male) and purplish (female)
Sun: Full sun to part shade
Water: Medium to wet
Maintenance: Low
Suggested Use: Shade Tree
Flower: Insignificant
Culture
Best grown in medium to wet soils in full sun to part shade. Also tolerates dry, infertile soils. Best in cool climates. Does not perform well south of USDA Zone 7.
Noteworthy Characteristics
Alnus japonica, commonly called Japanese alder, is a conical to pyramidal deciduous tree that is native to temperate forests, streambanks, swamps and roadsides in northeastern Asia and Japan. It typically grows to 40-60' (less frequently to 80') tall. Narrow, acuminate, serrulate, ovate to elliptic, dark green leaves (to 5" long) are wedge-shaped at the base and light green underneath. No appreciable fall color. Flowers are monoecious. Long, pendant, yellow-brown male catkins appear in clusters. Short erect female catkins are followed by ellipsoidal fruiting cones (3/4" to 1 inch long) composed of winged seeds.
Genus name is the Latin name for alder.
Specific epithet means of Japan.
Problems
No serious insect or disease problems.
Uses
Uncommon in the U.S. Good selection for difficult sites such as moist low spots or dry sites with poor soils. Woodland areas.