The Incredible Clethra alnifolia

By Sue Hunter, owner, Heartwood Nursery

Few native shrubs are as versatile and fragrant as Clethra alnifolia, commonly called Sweet Pepperbush or Summersweet. Introduced into cultivation in the early 1700s by American botanists, Clethra alnifolia was also planted at Monticello by Thomas Jefferson in the 1750s.

While the popularity of Clethra alnifolia has steadily grown through the centuries, its reputation is skyrocketing now as more gardeners appreciate it as a pretty, scented, compact, and low-maintenance flowering native shrub ideal for smaller gardens.

Clethra alnifolia 'Ruby Spice' and 'Seafoam' are naturally occurring, straight species selections and are available here at Heartwood. They are not hybrids bred by humans.

Blooming July through August, Clethra is a butterfly and pollinator magnet that pairs well with other shrubs, such as Elderberry, Gray Dogwood, and Blueberries.

For a distinct and diverse perennial border in front of Clethra, plant Mountain Mint, Joe Pye weed, and Asters. Lovely color will last through late fall. 

Clethra tolerates a wide range of growing conditions, from full sun to shade and dry to moist soil. It's natural habitat tends to be the understory of the eastern woods of the Coastal Plain, with random dispersion in transitional Coastal Plain/Piedmont areas.

Autumn leaf color is a bright golden yellow. 

Clethra flower clusters yield to tiny brown capsules that contain seed the size of a speck of dust. Winter songbirds depend on the seed and branching habit for food and shelter.

For all these reasons, the incredible Clethra is a great alternative to the invasive nonnative Buddleia davidii, butterfly bush.

Did you know Clethra flowers and leaves have high saponin content? A natural foaming soap can be made by gathering a handful of flowers or leaves and rubbing them in your hands under a trickle of water.

Clethra flowers and leaves have high saponin content, making them a natural foaming soap with water.

Have you had success with a Clethra from us? Email photos and a description to officeatheartwood@gmail.com. We'd be happy to share it in a future issue of our monthly newsletter, Heartwood Native News.