Roundleaf Leather Root (Psoralea orbicularis)
At a glance
- Lifecycle
- Perennial (hardy)
- Exposure
- Full sun
- Frost limit
- −23.3 °C
Cultivation
Succeeds in an ordinary garden soil. We have very little information on this species but it is growing at Kew in the system beds and seems to be thriving there[K]. Plants are very intolerant of root disturbance, they are best planted out into their permanent positions whilst still small. 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.
Propagation
Pre-soak the seed for 24 hours in warm water and then sow in early to mid spring in a greenhouse. Either sow the seed in individual pots or pot up the young seedlings as soon as possible in order to avoid root disturbance. Grow them on in the pots until planting out in their final positions. It is usually impossible to transplant this species without fatal damage to the root. Division in spring. With great care since the plant resents root disturbance. It is virtually impossible to divide this species successfully.
Edible uses
Leaves - cooked.
Medicinal uses
A decoction of the root used as a blood purifier and in the treatment of fevers.
Material uses
The plant is a good soil stabilizer in its natural environment.
Habitat
Moist places below 1500 metres in California.
Native range
South-western N. America.