European mountain-ash has escaped cultivation in northern Ohio but does not threaten native plant populations. These small, deciduous trees have rather large, scaly buds. Pinnately compound leaves are borne alternately along the stems. Flowers are showy, perfect, and borne in flat-topped corymbs. Fruit is a red pome and borne in showy clusters.
Sorbus aucuparia–European Mountain-Ash
Sorbus americana–American Mountain-Ash
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| European Mountain-Ash (Rowan Tree) |
American Mountain-Ash–Sorbus americana
American mountain-ash is a small tree, sometimes appearing as a shrub, that reaches 10—20 feet in height with attractive foliage and fruit. This tree is native in areas of Ohio with cooler summers. It occurs from Nova Scotia, Canada, south along the Appalachian Mountain spine to North Carolina. American mountain-ash is found in cool, mountain valleys. This tree should be grown only in the lake-effect areas of Ohio.
Winter buds scales are glabrous, or ciliate at the most, and sticky. Young branches rapidly become glabrous. These characteristics readily separate this tree from the European mountain-ash. Leaves are odd-pinnate with 11—17 leaflets that are 11/2—4 inches (4—10 cm) long and of a light green color.
White flowers are smaller than the European mountain-ash and borne in May. Cymes are 21/2—5 inches (6—13 cm) across. The individual flower is only 1/4 inch (6 mm) across. Fruit is bright red and matures in October.
European Mountain-Ash (Rowan Tree)–Sorbus aucuparia
The European mountain-ash is an attractive tree planted for ornamental purposes and grown for the showy, orange-red fruit. It is a round-headed tree that grows to 50 feet. Numerous cultivars are available in the nursery trade. This tree grows well only in the lake-effect areas of Ohio. This tree generally performs poorly and is short-lived in Ohio landscapes away from Lake Erie.
Winter bud scales are large, white, woolly, and not sticky. Young branches are pubescent. Leaves are odd-pinnate with nine to 15 leaflets. Leaflets are smaller than the American mountain-ash leaflets at 3/4—2 inches (2—5 cm) long. Stipules are broad and coarsely toothed.
The tree is usually many-branched with smooth, grayish bark. Flowers are white, 1/3 inch (8 mm) in diameter. Flowers are larger than the American counterpart and borne in May in cymes that are 4—6 inches (10-15 cm) across. Fruit is orange-red and matures in August or September. Fruit forms a massive, 4—6-inch (10—15 cm) head of orange-red pomes in fall. Fruit is favored as food for birds and normally is retained until the end of the year.