Blue Cohosh

Blue Cohosh

Botanical Name: Caulophyllum thalictroides

En Français: Caulophylle


Colour: Blue, Green

Blue cohosh is an attractive wildflower, with an unusual display of the spherical blue fruits held stiffly above the leaf canopy. The roots were widely used my Native Americans as an herbal medicine to treat a range of ailments and as a general tonic.  However, the plant contains chemicals that can cause cell damage.

There are two species of Blue Cohosh: Caulophyllum thalictroides and Caulophyllum giganteumCaulophyllum thalictroides (Blue Cohosh) generally has lighter greenish flowers which bloom after the leaves have opened. Caulophyllum giganteum (Giant Blue Cohosh) has dark purple/red flowers which open with or before the leaves.

Other Characteristics

Pollinators: Bees

Sun/Shade: Shade

Planting and Care Considerations

Blue cohosh is a forest herb, and therefore requires conditions that mimic a forest floor including shading and mulch.

Plants may be grown from seed, but usually will not flower until the third or fourth year. May be divided, but established plants are generally best left undisturbed.

Spicebush (Lindera benzoin), pagoda dogwood (Cornus alternifolia), lady fern (Athyrium filix-femina), blue phlox (Phlox divaricata), sugar maple (Acer saccharum)

Spread: 25cm

Water: Contant humidity.

Best Soil: rich, moist, neutral to slightly acidic soils

Growth Habit: 

More Information

Flowers get replaced with blue berries in the late summer.

Blue cohosh is used for medicinal purposes (anticonvulsant, antirheumatic, febrifuge, emetic, sedative, and most notably, a gynecologic aid) but has the potential to poison people especially children.