Description

Caulophyllum thalictroides is a multi-branched woodland perennial with a bushy habit whose height will vary depending on environmental conditions from 1 to 4'. It's compound, lobed foliage is exceptional, and reminiscent of meadow rues (Thalictrum spp), hence the specific epithet thalictroides which means Thalictrum-like. The leaves are purple when they emerge, turning smokey-blue as they mature, and ultimately shades of yellow in fall before the plant goes dormant. Although the flowers are intricate and interesting, their yellowish-green color and small size, renders them rather inconspicuous. The berries, however, are very showy. Emerging green, they mature to form clusters of purple grape-like fruit that will persist well through winter and provide visual interest when there is little else around.

Cultivation

Blue cohosh grows in neutral to slightly acidic soil, rich in organic matter. It will prefer a shady spot where it will not be allowed to dry out in summer. It is best used in groupings where it will slowly colonize by means of rhizomes. To highlight its foliage and provide textural contrast, it can be combined effectively with ferns or sedges. It has a short bloom time in April or May. Zones 3-8

Propagation

Can be propagated by division, but with care because this species does not like to be disturbed. Propagation from seed is slow, as seedlings may take up to 4 years to produce flowers.

Additional Notes

The berries are unpalatable to wildlife until they have undergone several freeze-thaw cycles, and therefore persist well into winter, providing food when little else is available.