White Alder Clethra barbinervis

Japanese clethra is a dense, deciduous, oval-shaped flowering shrub maturing to 9 feet high by 9 feet wide, although specimens do reach heights of 20 feet. In its native Japan, it is typically found in wooded hills and mountains, in sunny deciduous forests on mountains, or in stony and dry places at elevations of 3200 to 5000 feet.This plant prefers partial shade as well as moist, lime free, organically rich, acidic, and well-drained soil. It will tolerate a sunny site and is generally hardy, although it can suffer from harsh winter winds in Zone 5 where it may not be reliably winter hardy throughout. Summer cuttings can be easily rooted and it will spread through suckering to form colonies.

Japanese Clethra produces dropping, fragrant white flowers on the current season's growth in summer into early fall and glossy, dark green leaves which turn bright yellow (sometimes red) in autumn for good fall color. Dark brown seed capsules persist into winter and the polished, grayish-brown bark exfoliates. Flower spikes are more horizontal and drooping and less fragrant than those of Clethra alnifolia (Summersweet). Japanese Clethra is trouble-free shrub useful in small grouping in conspicuous locations where its summer bloom, good fall color, bark and seed spikes) can be viewed.

The genus Clethra comes from the Greek klethra  for alder, which this plant's leaves resemble. The species barbinervis means with veins barbed or bearded.

Diseases, Insect Pests, and Other Plant Problems:

No known diseases or insect pests. Spider mites can be a problem in hot, dry sites. Spring growth can be damaged by a late frost and may need protection.