Alderleaf Pepperbush Clethra alnifolia

Sweet pepperbush, is a deciduous shrub in the Clethraceae family.  It may grow to 5 to 10 feet. and often spreads into mounded clumps. It is native to eastern North America from Maine south to Florida and west to Texas. In the wild, it is often found in swamps, damp thickets, and sandy woods.

The leaves are alternate with a finely toothed margin. The bark is gray and loosely striped. Small, white flowers occurring in dense clusters on long 3 to 6 inch terminal spikes mature in late summer. The flowers produce high quality nectar and pollen that supports hummingbirds, butterflies, bees and other pollinators. The shrub produces a brown, dry capsule that matures in the fall and provides seed to birds during the winter. Sweet Pepperbush is unique among flowering shrubs because it blooms in shady locations in late summer when few other shrubs are in bloom.

This shrub is often grown as a screen, or as a specimen, on in groupings as a border. It prefers moist, sometimes wet, acidic soil with organic material and tolerates short periods of drought and flooding once established. It tolerates full sun to partial shade, but will not tolerate a hot, dry site. Dormant plants are hardy to about -22 degrees F (-30° C.). It is a good bee plant and the flowers are very aromatic. When grown in conditions similar to its native habitat, it will produce suckers and eventually form small thickets. However, it responds well to pruning.

Insects, Diseases, or Other Plant Problems:  Spider mites may be a concern in dry conditions.  Resistant to Phytophthora root rot.  When planted in the proper site, it is insect- and disease-resistant.

VIDEO: Part of the Native Plant Picks series from the North Carolina Sea Grant led Coastal Landscapes Initiative.

Additional video on Clethra alnifolia by Andy Pulte for “Landscape Plant Identification, Taxonomy and Morphology” a plant identification course offered by the Department of Plant Sciences, University of Tennessee.