Black Cohosh is an upright rhizomatous perennial native to eastern North America. It is found in a variety of woodland settings from Maine south to Georgia and west to Missouri and Arkansas. It prefers rich moisture-retentive soils in partial to full shade and can be slow to get established. Ideally, it wants 2-3 hrs of morning sun. if light is too limited, it may fail to flower. Plant in an area protected from strong winds as it can grow to heights of 6 or more feet. The leaves are attractive and the showy flowers are followed by interesting seedheads. although the flowers have an unpleasant, somewhat medicinal odor, the seedheads are often utilized in flower arrangements. It is attractive to wildlife. This plant adds a vertical accent to the back of the border of a shady cottage garden or woodland setting. Insects, Diseases, or Other Plant Problems: Rust and leaf spot are occasional problems of this plant. More information on Actaea .
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
Dappled Sunlight (Shade through upper canopy all day) | Deep shade (Less than 2 hours to no direct sunlight) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
High Organic Matter
Soil pH
Acid (<6.0); Neutral (6.0-8.0)
Soil drainage
Good Drainage | Moist
NC region
Coastal; Mountains; Piedmont
Mature size
Height: 4 ft. 0 in. - 7 ft. 0 in. | Width: 2 ft. 0 in. - 4 ft. 0 in.
Growth rate
Medium
Maintenance
Low
Canopy layer
4 - Herbaceous (3-15 ft)
Form & Appearance
Habit / form
Erect
Texture
Medium
Foliage
Deciduous
Leaf color
Green
Leaf type
Compound (Pinnately , Bipinnately, Palmately)
Leaf arrangement
Alternate
Leaf shape
Obovate
Leaf margin
Lobed; Serrate
Leaf value
Showy
Leaf size
> 6 inches long, > 6 inches wide
Hairs present
No
Leaf detail
The basal leaves are up to 3 ft long and broad, forming repeated sets of tripinnately compound leaflets. The terminal leaflet is usually 3-lobed. Leaflets are obovate to ovate-lanceolate in outline, 2-5 lobed, with the margins toothed or incised.
Flower color
White
Flower value
Showy
Flower form
Raceme
Flower shape
Star
Flower size
< 1 inch
Flower detail
Hundreds of tiny fluffy-looking creamy white flowers on 1-2 foot long racemes have no petals but consist of tight clusters of many stamens surrounding a white stigma. It has an unpleasant aroma. Flowering occurs from May to August.
Bloom time
Summer
Fruit color
Brown/Copper; Green; White
Fruit type
Follicle
Fruit value
Showy
Fruit size
< 1 inch long, < 1 inch wide
Fruit detail
Small dry seed pods from July to September.
Stem color
Green; Purple/Lavender
Stem detail
The flower stem is green to purplish
Wildlife & Ecology
Native status
Native
Origin
SE USA
Distribution
USA: AL , AR , CT , DC , DE , GA , IA , IL , IN , KY , MA , MD , ME , MI , MO , MS , NC , NJ , NY , OH , PA , SC , TN , VA , WV Canada: ON , QC
Wildlife value
It is a host plant for Spring Azure, Holly Blue, and Appalacian Azure (Celastrina neglectamajor) butterflies/larvae. As in the butterfly's name, Appalachian Azure's flights are only in the Appalachians which occur just once a year in May to June. Interestingly, the caterpillars are known for eating flowers (versus what many people think of caterpillars eating leaves).
Attracts
Butterflies; Hummingbirds; Pollinators; Songbirds
Play value
Attractive Flowers
Food & Medicine
Harvest time
Summer
Fruit type
Follicle
Uses (ethnobotany)
Its roots and tubers were used medicinally by Native Americans. It continues to be used in herbal medicine today, although it has not been widely researched, and is not recommended as an effective treatment for any specific medical conditions. Also used to make insect repellant.