Caulophyllum thalictroides

Family:

Berberidaceae

Common Name(s):

Blue cohosh

Flowering Time:

May

Fruit/Seed Maturation Sign:

Fruit turns blue

Fruit/Seed Collection Dates:

Early September

Seed Cleaning:

None required

Storage:

Intolerant of dry storage (Cullina 2000)

Restoration Potential:

Medium to low by seed (requires patience)

Notes

Scarify seed (nick or cut a slit in seed coat); sow in fall outside or cold stratify in moist sphagnum until planting following spring; expect to see seedlings 2 years after planting (Mabry 2023).

Of 330 seeds planted in a central Iowa demographic study, 83 (25%) germinated and 45 plants survived to year 5; 18 flowered after an average of 10 years (Mabry 2023); scarify seeds (seedcoat very hard); no germination until year 2 (Mabry, personal observation).

Survival of mature transplants added to a woodland degraded by cattle grazing in Wisconin declined over the eight years that they were monitored (Ellarson and Craven (1982).

Produces few seeds per plant with low vegetative spread (Barkely 1986, Gleason and Cronquist 1991, Cullina 2000); rootstock knotty and thickened (Runkel and Bull 2009).

Blue Cohosh (Caulophyllum thalictroides)