Flower:

Flat or rounded cluster to 7 inches across of short-stalked flowers at the tips of 1-year-old branches, blooming when leaves are mature. Flowers are 1/3 to ½ inch across, white with 5 rounded petals. In the center are 2 to 4 short, yellowish styles surrounded by about 20 creamy white, ascending to spreading stamens. The calyx around the base of the flower has 5 short, triangular lobes, and covered in long, silky white hairs. Flower stalks are also covered in, long, soft hairs.

Leaves and bark:

Leaves are alternate, 4 to 9 inches long, compound with 11 to 15 leaflets, occasionally more. Leaflets are oblong-elliptic, 1 to 1½ inches long, ¼ to ¾ inch wide (2.2 to 3.5 times as long as wide), rounded to pointed at the tip, asymmetrical and mostly rounded at the base, and stalkless. Edges are sharply and coarsely single or double-toothed. The upper surface is variably hairy, the lower densely covered in soft hairs. The compound leaf stalk is variably hairy and often reddish. Leaves turn golden yellow to orange-red in fall.

Buds are green to dark purple and covered with long, white hairs. New twigs are green to brown and hairy, becoming reddish with scattered, pale lenticels (pores), and hairless the second year.

Older bark is gray to bronzy, becoming rough with scattered horizontal lenticels, developing plates that eventually peel off. Trunks are single and can reach up to 10 inches diameter at breast height (dbh).

Fruit:

Fruit is a cluster of bright orange-red, ¼ to 3/8-inch, round, berry-like pomes (fleshy with a chamber of seeds in the center, like an apple). Fruit matures in late summer and persists through winter.

Notes:

European Mountain-ash was once widely planted as an ornamental and has occasionally escaped cultivation, but has gone out of favor in the nursery trade due to its high susceptibility to sun scald, various canker diseases, and bacterial fire blight. Similar to the native American Mountain-ash (Sorbus americana) and Showy Mountain-ash (Sorbus decora), it is most easily distinguished by the hairy leaves, leaf stalks, calyx, and white-hairy winter buds. Leaflets are usually smaller, more coarsely toothed, and less tapering at the tip than both of the natives. The terminal tooth on both natives is typically slender and elongated where the terminal tooth on European Mountain-ash is not much different than the lateral teeth.