white flower of clethra alnifolia native shrub

Flowers of summersweet, also called sweet pepperbush. Photo: M. Talabac, University of Maryland Extension

Updated: June 21, 2023

Growing summersweet

Clethra alnifolia
Deciduous shrub

Maryland Distribution: Coastal Plain
Height: 6-12’ (dwarf cultivars are 2-4’)
Flowers: showy white or pink flowers in July-August
Fall color: yellow
Sun: full sun to shade
Soil: moist to wet soil; pH 4.5-6.5

Garden Uses: Summersweet (Clethra alnifolia), also called sweet pepperbush, is a Maryland native plant found in forested wetlands, floodplains, and swamps. Spikes of highly fragrant flowers bloom on the current season’s woody stems in mid-summer. The seed capsules turn brown and persist on the plant in fall and winter. The foliage turns golden yellow in autumn.

This plant is adaptable to all soil textures (sand, silt, clay) and tolerates periodic flooding, even by partly salty (brackish) water. It spreads by suckers, meaning new stems arise from the root system. 

clethra alnifolia native shrub growing near a lake
Sweet pepperbush in bloom (white flowers) paired with native red cardinal flowers. Photo: M. Talabac, University of Maryland Extension

Summersweet is ideal for a rain garden, pollinator garden, fragrance garden, privacy screen, or shrub border. It also can be used for erosion control on slopes, or near a pond or downspout. Grows in similar conditions favored by winterberry holly and Virginia sweetspire.

Cultivated varieties vary in size. Some grow to 5-8’ in height while dwarf cultivars mature in the 2-4’ range. Smaller forms of Clethra alnifolia include:

  • Sugartina® ‘Crystalina’ - 3’ x 3’
  • Summer Sparkler® (‘Novacleein’) - 3-4’ x  3-4’ 
  • ‘Hummingbird’ - 2’-4’ x 3-5’ 

Wildlife: Summersweet is highly valuable to native wildlife. The flowers provide food for native bees, butterflies, and hummingbirds, and a variety of songbirds eat the seeds. It is a host plant for the Sweet Pepperbush Nola Moth.

This plant has few pest or disease problems and it is deer-resistant.

yellow leaves of clethra alnifolia native shrub
Native summersweet (sweet pepperbush) turns golden yellow in autumn. Photo: M. Talabac, University of Maryland Extension

References

Dove, Tony and Ginger Woolridge. 2018. Essential Native Trees and Shrubs for the Eastern United States: The Guide to Creating a Sustainable Landscape, Charlesbridge, Watertown, MA.

Slattery, Britt E., et. al. 2005. Native Plants for Wildlife Habitat and Conservation Landscaping, U.S. Fish & Wildlife, Chesapeake Bay Field Office, Annapolis, MD. 82 pp.

Still have a question? Contact us at Ask Extension.

Compiled by: Christa Carignan, Horticulturist & Coordinator, Home & Garden Information Center. 2022

Still have a question? Contact us at Ask Extension.