Sorbus alnifolia
Korean Mountainash
Mature Size, Growth, Longevity
40-50' tall & 20-30' wide (sometimes to 60' tall & 50' wide). Habit is pyramidal to oval to rounded. Growth rate is medium to fast.
Native Range
Native to Korea, Central China & Japan. Introduced into cultivation in 1892.
Flower and Fruit Details
Flowers are showy, white, 1/2", in 2-3" clusters (corymbs) of 6-10 flowers. Alternate bearing, heavy only every other year. Best fruit display of any mountainash, pinkish-red to red-orange to scarlet fruits, Sept/Oct, 3/8-5/8". Fruits are rounded to obovoid & are dotted w/ lenticels,
Leaf and Bark Features
Deciduous: Leaves simple, alternate, ovate, dark green, 2-4" long and 3/4-1.5" wide, unevenly serrated on margin, acuminate at tip, w/ 6-14 vein pairs.Vigorous shoots may be pubescent. Fall color is yellow, orange & golden-brown. Notable Bark: Young stems lustrous reddish-brown, w/ raised gray lenticels, which become diamond-shaped on older stems. Bark is beech-like on old trunks, smooth & gray.
Culture and Care
Adaptable to various sites, soils and pH conditions. Not tolerant of pollution and urban settings or low, wet, poorly-drained sites. Zone 4-7. Prune in late winter or early spring. Requires little cultural attention. Continued high night temperatures in Zone 7 are hard on the tree. Possible problems include fireblight, crown gall, canker, leaf spot, scab and borers, although more resistant than other mountainash species.
Strengths, Weaknesses, Other Facts
Good wildlife value. 4-season interest: Spring, summer, fall & winter. Author & plantsman, Dr. Michael Dirr, says this is one of his "favorite all-around trees".
Suggested Uses
Makes an excellent specimen tree for lawns.