Black Cohosh
Plant of the Week July 11, 2022
Black cohosh (Actaea racemosa, Cimicifuga racemosa)
By Nancy Arnold, Anoka County Master Gardener
Black cohosh is a perennial native to the Eastern United States and Canada. It is also referred to as black snakeroot or bugbane. The name bugbane comes from the insect repellent-like smell the plant gives off. It was the wildflower of the year in the U.S. in 2017. It used to be abundant in native areas, but it's largely depleted due to habitat loss and commercial harvest. Native Americans used black cohosh as an analgesic, sedative, and anti-inflammatory. Now, it is available as a dietary supplement to treat various gynecological conditions.
While not native to Minnesota, it is hardy to zone 4 and can grow in the lower half of the state. It grows best in rich moist soil and in part-shade. Once established it can tolerate a variety of conditions, including sun and drought. It spreads slowly by rhizome as well as by seed. Black cohosh is a good specimen for the back part of a shade garden and will not become invasive. It forms a neat, compact mound about three to four feet tall. It grows spike-like stems of white blooms that reach up to six feet tall. Blooms arrive in late July to early August. They emit a mild, sweet, but fetid odor that attracts bumblebees and other pollinators. The seeds are a favorite of birds but are generally deer resistant. This plant is toxic to humans and animals if ingested in large amounts.
