Blue Cohosh, Caulophyllum thalictroides

Blue Cohosh

Caulophyllum thalictroides

Sun Shade:
Bloom Time: Spring
Zones: 3, 4, 5
Soil Conditions: Clay, Loam
Soil Moisture: Medium
Color: Yellow
Fragrance: No
Height: 2 - 4 feet
Spacing: 1 foot


Blue Cohosh (Caulophyllum thalictroides) is a native perennial which grows 1-3 feet tall on strong, upright stems. It is valued not for its flowers but for its lacy, ternately-compound, blue-green foliage and its erect clusters of blue, fruit-like seeds. Leaves appear at mid-stem, emerging a smoky blue in spring and turning bluish-green at maturity. Young plants are covered with a whitish, waxy bloom. Inconspicuous, brownish-green to yellowish-green flowers (1/2 inch diameter), each with 6 pointed sepals, appear in spring.

The blooming period occurs from mid- to late spring before the leaves have fully developed. Afterwards, the flowers are replaced by berry-like seeds that are about 1/3-inch across, globoid in shape, glabrous, and glaucous. These seeds are initially green, but they later become bright blue at maturity during the summer. The seed coat is fleshy and contains carbohydrates. The root system is rhizomatous and fibrous.

Habitats include rich mesic woodlands, bluffs, and wooded slopes of large ravines. This relatively conservative wildflower can be found in woodlands dominated by either oaks or maples where the native ground flora is still intact.

The soil should also contain abundant organic matter from decaying leaves and other plant materials, as typically occurs underneath trees. The large seeds are difficult to germinate. Best grown in shady woodland areas in rich, moist, neutral to slightly acidic soils. Needs consistently moist soils that do not dry out. Plants may be grown from seed. May be divided, but established plants are generally best left undisturbed.

Plant Notes and Herbal Uses
  Can spread very slowly by rhizomes over time to form colonies.
  Blue Cohosh is long-lived.
  Will not flower until the third or fourth year.
  Called squawroot and papoose root because of its use by native Americans to assure quick infant delivery and to ease menstrual cramps.
Further Information

 Wisconsin Fruit Trees
 Wisconsin Edible Berry Shrubs
 Widsconsin Edible Plants-Eat On The Wild Side
 8 Dandelion Recipes
 Wisconsin Native Plant Nurseries