A deciduous tree up to 30 ft high, but more often a shrub; young shoots glabrous, older bark grey; buds sessile. Leaves broadly ovate, pointed, rounded or slightly heart-shaped at the base, the margins cut into numerous very fine, slender teeth, giving them a fringe-like appearance; 2 to 4 in. long, 11⁄2 to 3 in. wide; hairy when very young but glabrous later except for axil-tufts of down beneath; stalk 1⁄2 to 11⁄4 in. long; veins in eight to eleven pairs, bright green on both surfaces. Male catkins 2 in. long; fruits egg-shaped or cylindrical, 5⁄8 to 3⁄4 in. long, borne on slender, glabrous stalks.
Native of Japan, where it is common on many of the higher mountains; introduced in 1914. It belongs to the same group of alders as A. viridis, but is distinguished by the often heart-shaped base of the leaves and their fringe-like toothing. Very hardy.