Commonly known as summer-sweet or sweet pepperbush, clethra is an essential shrub for gardeners who crave fragrance. The 4 inch (10.2 cm) long bottle-brush-shaped flower spikes appear in mid- to late summer and last into fall, filling the air with their spicy-sweet perfume and attracting bees and butterflies. Not only are the blossoms welcome at a time when little else is in bloom, but the foliage is lovely all season. Ribbed and lightly toothed, the oval green leaves are downy when young and turn a clear yellow in autumn.
Clethra is native to the eastern woodlands of North America, where it usually grows as an understory tree. When given good garden soil and at least a half day of sun, it grows into a robust, naturally rounded bush up to 8 feet (2.4 m) tall. Clethra’s growth habit is also affected by soil moisture. An ideal shrub for damp locations, clethra transforms an abundant water supply into numerous leafy stems. In drier sites, it is more likely to grow tall with a lean profile.
Grow it along a woodland edge with other shade-tolerant plants, such as serviceberry, hydrangea, or dogwood. Or use it as a specimen plant at the back of a border that receives partial shade, mixing it with such companions as Japanese anemone, cohosh, perennial geranium, and ornamental grasses. Clethra also makes a fine freestanding shrub when used to define the edges of a lawn; smaller cultivars can mark an informal path. The shrubs withstand salt spray and are therefore useful for seashore sites; they also tolerate the shade of buildings when planted around foundations. And because it leafs out late in spring, clethra is a good shrub to underplant with any number of spring-flowering bulbs.
The Reader’s Digest Association, Inc./GID
Clethra features bottle-brush-shaped flower spikes.
