948 Clethra alnifoliaCommon Names: sweet pepperbush, summersweet Family: Clethraceae (sweet pepperbush Family)
Sweet pepperbush (or summersweet) is a spreading deciduous shrub that gets 4-8 ft (1.2-2.4 m) tall and blooms in summer with showy upright clusters of little white flowers. The flowers have five petals and are about a third of an inch across, borne in dense racemes at the ends of the twigs. They have a wonderful sweet, spicy, slightly pungent fragrance. The leaves are alternate, 2-3 in (5-7.6 cm) long and serrated towards their tips. They turn golden yellow in fall. In nature, sweet pepperbush usually grows in shrubby thickets along with wild azaleas (Rhododendron canescens) and blueberries (Vaccinium ashei), and it rarely gets more than 4 ft (1.2 m) tall. At least a dozen selections have been named, including 'Hummingbird', which is compact and gets only 2-3 ft (0.6-0.9 m) tall; and 'Pink Spires' with rosy pink flowers.
Sweet pepperbush, Clethra alnifolia, grows naturally in wet forests, pine flatwoods, swamps, bogs, and along woodland streams from Maine, south to northern Florida and west to eastern Texas.
CultureSweet pepperbush likes an acidic soil, so never add lime. Cultivate as you would an azalea or blueberry bush. Sweet pepperbush is moderately salt tolerant, and can be grown near (but not directly behind) the beach. Light: Pepperbush will grow in full sun or in the shade. It probably does best in a light, dappled shade. Moisture: Sweet pepperbush grows naturally in poorly drained, moist soils, but once established in cultivation, it thrives on drier, well drained soils as well. It will get larger and produce more suckers if provided plenty of water. Hardiness: USDA Zones 4 - 9. Propagation: You can start new pepperbushes easily from soft stem cuttings taken in summer. You also can divide the root mass or grow from seeds which germinate readily.
Sweet pepperbush is an outstanding shrub for a naturalized garden. It will gradually spread by sending up new shoots, forming a thicket of low bushes. Allow pepperbush to naturalize along a stream or pond where its suckering will help control erosion. Its fragrant snowy white flowers attract bees and butterflies, and the flowers last for 6 weeks or more in the heat of summer when most flowering shrubs are taking a break. Use sweet pepperbush in a mixed shrub hedge or border. Pepperbush can be pruned to maintain a small size, or allowed to grow naturally - it will probably never exceed 6 ft (1.8 m) in height anyway. Sweet pepperbush has a wonderful fragrance, showy flowers, attracts butterflies, grows in the shade, blooms in mid summer, has nice fall color, stays small - in short, sweet pepperbush is one of the finest deciduous shrubs in cultivation.
Clethra is the only genus in the family, Clethraceae, which is very closely related to the heath family, Ericaceae. Besides this one North American species, there are about 40 other species of Clethra which occur in eastern and southeastern Asia. Some of these are available from nursery centers, but the American species is still our favorite.
Steve Christman 4/3/02; updated 8/11/03, 6/15/11