Clethra alnifolia aka Coastal Sweetpepperbush

Clethra alnifolia is a shrub that sheds its leaves each fall. Gardeners call it summersweet or sweet pepperbush. It belongs to the Clethraceae family. Its native range runs from southeastern Canada south to Texas. In the eastern United States, it reaches from Maine to Florida. Wild plants grow in swamps, damp woods, and coastal sites. Many grow near streams or other water.

In gardens, plants often stand 3–6 feet [0.9–1.8 metres] tall. They spread about 4–6 feet [1.2–1.8 metres] wide. Some sources give heights near 8 feet [2.4 metres]. Virginia Tech reports plants reaching 10 feet [3 metres]. Many stems form a dense, rounded or upright shrub. Shoots rise from the roots and can form thickets. Young stems are brown; older bark turns gray-brown and scaly. The glossy green leaves grow one at a time along stems. Each simple leaf has toothed edges and pinnate veins. Leaves emerge late in spring. Fall shades range from yellow-green to gold and brown.

Small white flowers open in upright racemes at branch tips. They bloom on the current year's growth. Most sources place flowering in July and August. North Carolina State also records blooms starting in June. Their sweet scent draws bees, butterflies, and hummingbirds. Small, dry capsules turn brown in fall. They can stay on the shrub through winter or longer. Birds and small mammals eat the fruit. These lasting capsules add interest after the leaves fall.

Give this shrub moist, acid soil rich in organic matter. It grows in sand, loam, or clay. Part shade suits it best, though it tolerates deeper shade. It also grows in sun if the soil stays moist. Avoid hot, dry sites and do not let soil dry out. Established plants tolerate brief droughts and floods. Sources list USDA zones 4–9 and RHS hardiness H5. Prune in late winter when needed. Remove root shoots to keep a defined shape. Seeds, summer cuttings, and divided suckers offer ways to grow more plants.

Use summersweet in borders, screens, rain gardens, or woodland plantings. Its late flowers bring scent to shaded gardens. Care is light once the site suits it. Pests and disease seldom cause trouble. Spider mites can become severe in hot, dry spots. Plants resist Phytophthora root rot. Plants For A Future lists no known food or medicinal uses. It reports no known hazards, rather than proven safety. It also records flower stalks as a soap substitute.