In Bloom: Black Cohosh

In Bloom: Black Cohosh

Black Cohosh. Anne Holmes, artist

By Suzanne Wodek

Sometimes referred to as bugbane or black snakeroot, Actea racemosa is an upright, native perennial that is easily grown in organically rich, moisture-retentive soil. The common name of bugbane is a reference to the insect repellent smell the plant gives off. Black refers to the dark color of the rootstalk. The name cohosh comes from an Algonquian word meaning rough, referring to the feel of the rhizome.

Black cohosh adds architectural height and summer bloom interest to your border or shade garden. It typically grows to a height of four to six feet, but can reach eight feet in ideal conditions. Also effective in cottage gardens, woodland gardens and naturalized areas, the plant’s astilbe-like foliage is an attractive deep green topped with white, candelabra-shaped fragrant flowers. Site this plant in a location sheltered from strong winds in part to full shade.

The good news for gardeners in this area is the entire plant is generally deer and rabbit resistant. The flowers provide both nectar and pollen to insect visitors. The caterpillars of the butterfly Celastrina neglecta major, Appalachian azure, feed exclusively on black cohosh. Native Americans used this plant to treat general fatigue, kidney ailments, malaria, rheumatism, sore throat and gynecological disorders.

Also consider blue cohosh, Caulophyllum thalictroides, a native perennial in the barberry family. It only grows one to three feet tall and is valued not for its flowers but for its lacy, blue-green foliage. Spring flowers give way in summer to attractive blue berry-like seeds that resemble small grapes and provide good ornamental interest into fall after the foliage has declined. The berry-like seeds are poisonous. Blue cohosh does best in shady woodland areas of rich, moist, neutral to slightly acidic soil. Provide consistently moist soil that does not dry out.

If you have the proper conditions, both black and blue cohosh can provide spring through late summer interest in your shade garden.

The Botanical Gardens, located at 151 W.T. Weaver Boulevard, is a nonprofit organization housing a collection of plants native to the Southern Appalachian Mountains. Admission is free, but donations are appreciated and memberships are encouraged. Learn more at

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