Herb to Know: Black Cohosh

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Photograph by J. G. Strauch, Jr.

Cimicifuga racemosa
• (Sim-ih-SIFF-you-guh rass-eh-MOE-suh)
• Family Ranunculaceae
• Hardy perennial

The genus Cimicifuga comprises twelve species of erect her­baceous perennial plants that are native to north temperate regions. Black cohosh (C. racemosa), the species probably most familiar to herb gardeners, is a wildflower of moist or dry woods in eastern North America and is also cultivated as an ornamental.

Black cohosh produces clumps of strong stems 3 to 8 feet tall. Large, alternate green leaves are pinnately compound with toothed leaflets. Long, graceful wands of small, starry white flowers held above the foliage bloom from June through September. The flowers have no petals, and the greenish white sepals fall off soon after a flower opens, leaving a tuft of showy stamens surrounding a single pistil. The flowers are thought to be pollinated by green flesh flies.

The generic name Cimicifuga comes from the Latin cimex, a kind of bug, and fugare, “to put to flight”. Bugbane is the English equivalent. Both names refer to the belief that the plants’ strong odor repels insects. Indeed, tops of the “unpleasantly elder-scented” Eurasian species C. foetida used to be dried and stuffed into pillows and mattresses for this purpose. Racemosa means “in the form of a raceme” and refers to the arrangement of individual flowers on an elongated stalk.

The word cohosh comes from an Algonquian word meaning “rough” and refers to the plant’s lumpy blackish rhizomes. An alternate common name, rattletop, refers to the sound of the dry seeds in their pods atop the flower stalks.

Medicinal Uses

Native Americans used the rhizome to relieve menstrual cramps and to ease childbirth, hence another common name–squawroot. Blue cohosh (Caulophyllum thalictroides), a wildflower in the barberry family (Berberidaceae), is known as squawroot for the same reason. Black cohosh was an ingredient of Lydia Pinkham’s Vegetable Compound, a patent remedy for “female complaints” that was popular in the nineteenth and early twentieth centuries. It has also been used to treat arthritis, coughs, diabetes, tinnitus, dropsy, neuralgia, malaria, yellow fever, and so forth. The alternate common name black snakeroot (C. racemosa is only one of many herbs known as snakeroot) refers to the rhizomes’ use in poultices to treat snakebite.

Black cohosh has been considered both a relaxant and a mild tonic. Studies have shown extracts of the rhizome to be anti-inflammatory and to lower blood pressure in laboratory animals. Nevertheless, the U.S. Food and Drug Administration finds “no pharmacologic evidence of any therapeutic value.”

Large doses can cause nausea, dizziness, or miscarriage.

Other Uses For Black Cohosh

Black cohosh is not commonly used for food. However, the leaves of the Asiatic species C. simplex are eaten boiled, and the fragrant root is used as a spice. The flowers and seed heads of both species make good cut flowers.

Black cohosh is beautiful at the back of a shady border or woodland wildflower garden. It combines well with ferns and coarse-leaved plants such as hostas. C. simplex, similar to black cohosh but shorter, blooms in late fall. Fall-blooming anemones and heleniums are attractive companions.

Growing Black Cohosh

Black cohosh is hardy in zones 3 through 10. Ideal conditions are light shade and rich, moist, humusy soil; however, plants will tolerate full sun or full shade and can withstand summer drought when established. Amend lean soils with peat moss or compost. Set plants 2 feet apart. They need no staking. Mulch with compost or aged manure in the fall. Plants can remain where they are indefinitely, but to increase your stock, divide established plants in early spring. If you have none to divide, consider buying one and dividing it in a year or two. Propagating plants from seed is possible but not for the impatient: germination can take as long as a year. Holding seeds planted in moist potting mix for three months at 70°F followed by three months at 40° is reported to result in high germination.


• Edgewood Farm and Nursery, Rt. 2, Box 303, Stanardsville, VA 22973-9405. Catalog $2 (refundable). Plants.
• Nichols Garden Nursery, 1190 N. Pacific Hwy., Albany, OR 97321-4598. Catalog free. Seeds.
• Sandy Mush Herb Nursery, Rt. 2, Surrett Cove Rd., Leicester, NC 28748. Catalog $6. Plants.
• Thompson & Morgan, Inc., PO Box 1308, Jackson, NJ 08527-0308. Catalog free. Seeds.