Roundleaf Leather Root
Psoralea orbicularis

Family: Fabaceae or Leguminosae

What it is like

Psoralea orbicularis is a PERENNIAL growing to 0.1 m (0ft 4in) by 0.6 m (2ft). See above for USDA hardiness. It is hardy to UK zone 6. The species is hermaphrodite (has both male and female organs) and is pollinated by Insects. It can fix Nitrogen. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It cannot grow in the shade. It prefers dry or moist soil.

Height (m): 0.1

Where it is found

Moist places below 1500 metres in California.

South-western N. America.

Conservation Status:

Countries/locations it is found in

How it is used

Food

Rating: 1

Leaves - cooked.

Medicine

Rating: 1

A decoction of the root used as a blood purifier and in the treatment of fevers.

Blood purifier: Purifies the blood.

Febrifuge: Reduces fevers.

Other

Rating:

The plant is a good soil stabilizer in its natural environment.

Soil stabilization: Plants that can be grown in places such as sand dunes in order to prevent erosion by wind, water or other agents.

Nitrogen Fixer: Plants that fix nitrogen in the soil

How it is grown

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. 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.

Propagating it: 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.

Best place to grow: Cultivated Beds;

Habit: Perennial

Hardiness: 5-9

Growth:

Soil: Light (sandy), medium, heavy (clay)

Shade: No shade

Moisture: Dry, moist

Things to keep in mind

Although no specific mention of toxicity for this species has been found, at least some members of this genus contain furanocoumarins, these substances can cause photosensitivity in some people.

Its other names

Local names

Synonyms

Hoita orbicularis. (Lindl.)Rydb.