Species Name:  Caulophyllum thalictroides

Common Name: Blue Cohosh

Zone: 3 to 8

Distribution: New Brunswick to Ontario and Manitoba, south to Soouth Carolina, Alabama and Missouri.

Seed collection: Seed matures in late August to early September in the Northeast.  The seed turns from green to a deep sky blue color.  Seed can be collected any time during or after it begins to change color. Early collection of seed can reduce the time it takes for the seed to germination. Seed develops in a cluster of about one dozen seeds on the tip of the plant. Each seed holds a single embryo.  Strip seed from the stalk by hand.

Seed handling: Seed can be planted immediately or stored for later planting. Remove seed coat, which inhibits germination, soon after collecting.  Seed coat can be removed by placing seed in a food processor.  The hard seed coat protects the seed from injury. Begin stratifying seed in moist potting media for later planting. Seed can be planted in the spring of the first or second year or seed may be stored in moist potting mix until individual seeds begin to germinate then remove germinating seed  and plant.

Germination requirements: Seed must undergo repeated cycles of warm/moist stratification followed by cold/moist stratification to overcome seed dormancy. This deep dormancy means that most seed will not germinate until the third or fourth year.  Some seed may germinate in the second year in small percentages. The large seed produces a large seedling that grows quickly. Seedlings require half to full shade. 

Ecology: Blue cohosh grows in any moist rich woodland soil.  It  most often is found on calcareous soils and limestone outcrops but will also grow in slightly acidic soils. It can grow in great profusion in ideal conditions, carpeting acres of forest floor with knee deep blue-green foliage.  Its forests associates are frequently Sugar maple and many woodland forbs such as Trillium, Baneberry, Blood root and False Solomon seal.  It grows in moderate shade to deep shade. Blue cohosh is very resistant to deer browsing and for this reason it should be widely planted and encouraged where deer have decimated the understory vegetation.

Collect cohohs seed after it turns blue