Common Name:

General Information

Thermopsis montana is an erect, herbaceous perennial plant growing from a woody rootstock or rhizomes. It produces one to several moderately or few branched stems 20 - 80cm tall, occasionally to 100cm[].
The plant is harvested from the wild for local use as a medicine. It is sometimes used in local soil stabilization projects. It is grown as an ornamental in gardens, valued especially for its attractive foliage and lupin-like spires of yellow flowers[].
This species may become weedy or invasive in some regions or habitats outside its native range, and may displace native vegetation if not properly managed[].

Known Hazards

The plant contains alkaloids which are especially toxic in young plants and in mature flowering plants. Children suffered digestive tract problems, weakness and neurological effects after eating a few seeds or flowers[].
All parts of the plant are toxic. Ingesting 0.6 to 2.8g of dry foliage per kg of body weight for several days produces severe muscle degeneration in cattle. Ingesting 300 - 400g of dried plant material for 3 - 4 days will severely intoxicate cattle and slightly more can be lethal[].

Botanical References

Range

Western N. America - Washington to Montana, south to Arizona and New Mexico

Habitat

Moist sites in meadows or along streams seeps and springs; at elevations from 760 - 3,500 metres[].

Properties

Medicinal Rating
Other Uses Rating
Habit	Perennial
Height	0.60 m
Pollinators	Bees
Cultivation Status	Ornamental, Wild

Cultivation Details

Thermopsis montana is a very cold-hardy plant, able to tolerate temperatures down to around -30°c when fully dormant[].
Grows best in a sunny position, preferring a moist, well-drained, sandy to loam soil[]. Prefers a pH in the range 6.6 - 8.5[].
Plants can spread fairly rapidly by means of rhizomes, and can out-compete less vigorous plants[].
This species has a symbiotic relationship with certain soil bacteria; these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[].

Edible Uses

None known

Medicinal

A decoction of the plant is used as a cough medicine[].

The plant is burned, and the smoke inhaled, as a treatment for headaches[].

Agroforestry Uses:

The plant is used within its native range for soil and slope stabilization on roadside plantings[]. Thermopsis species in general have potential in soil conservation and stabilization projects. They fix atmospheric nitrogen, are drought-tolerant, deep rooting, and spread by underground root systems to form broad patches[].
The flowers are especially attractive to bumblebees[].

Other Uses

None known

Propagation

Seed - it has a hard seedcoat and may benefit from scarification before sowing in order to speed up and improve germination[]. This can usually be done by pouring a small amount of nearly boiling water on the seeds (being careful not to cook them!) and then soaking them for 12 - 24 hours in warm water. By this time they should have imbibed moisture and swollen - if they have not, then carefully make a nick in the seedcoat (being careful not to damage the embryo) and soak for a further 12 hours before sowing.