Common Name: Screw Bean

General Information

Prosopis pubescens is a much-branched, spiny, deciduous shrub or a tree with a round, spreading crown; it can grow from 2 - 10 metres tall. The short bole can be 30 - 40cm in diameter[, ].
The plant can be harvested from the wild for local use as a food, medicine and source of wood.

Known Hazards

None known

Botanical References

Range

Southwestern N. America - California, Nevada, Utah, Arizona, New Mexico and Texas, south to northern Mexico (Baja Norte, Chihuahua, Coahuila, Sonora)

Habitat

Found in creek and river bottoms, sandy/gravely washes, or ravines; at elevations from 100 - 1,300 metres[]. Found along streams, washes, floodplains, gullies, and in alkali sinks, oases, arroyos, and bajadas in the desert southwest[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Tree
Height	6.00 m
Pollinators	Bees, Insects
Self-fertile	No
Cultivation Status	Wild

Cultivation Details

Requires a sunny position in a well-drained soil. Plants can succeed in a wide range of soil conditions from light sands to heavy clays[]. Tolerant of moderately saline soils and also of alkaline conditions up to a pH of at least 10.6[]. Plants are very drought tolerant so long as their roots can reach the ground water; they can also withstand up to 3 months of the soil being inundated[].
Plants resprout from the base if they are cut down[]. Although top-killed bt severe forest fires, the plant will usually resprout from the base[].
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

Seedpods - raw or cooked[]. The immature pods can be harvested while still green and consumed raw as snacks[].
Mature pods, collected in the late summer, were traditionally pounded toa fine flour using stone pestles. The meal was set out to dry and then stored for later use. This powder was mixed with other foods or made into small cakes[].
The dark tan seedpod is tightly coiled into a spiral around 3 - 5cm long, and appears in pod clusters of 2 to 15. The seeds are very small, around 3mm long[].

Medicinal

The fibrous bark can be made into a dressing for wounds[]. A decoction of the bark was used as a wash on fresh wounds then the dried and powdered bark was applied to the wound over the next few days[].

A tea made from the roots has been used to treat problems with the menstrual cycle[].

A gummy exudate sometimes found on the bark can be soaked in water and the resulting liquid used as eyewash[].

Agroforestry Uses:

The pollen is said to be toxic to honeybees[].
This is one of several mesquite species that make excellent bee forage, the bees harvesting both nectar and pollen. The flowers are also a source of nectar for butterflies[].

Other Uses

The wood is used traditionally for construction, posts etc[].
The wood is an important fuel in its native range[]. The root wood makes a good fuel for cooking[].

Propagation

Like many species within the family Fabaceae, once they have ripened and dried the seeds of this species 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[].