Data provided by the participants of the Consortium of California Herbaria

View additional distribution information on the Jepson eflora

Prosopis pubescens, commonly known as Screwbean Mesquite or Tornillo, is a species of flowering shrub or small tree in the pea family, Fabaceae, that is native to the southwestern United States (Texas, Arizona, New Mexico, California, southern Nevada and Utah) and northern Mexico (Baja California, Chihuahua, Coahuila, Sonora). In California it is found primarily in desert areas from Inyo County southward. It has light brown bark, usually short, straight spines (1-3 centimeter/0.39-1.2 inches), twice-compound leaves, and numerous, small, yellowish flowers appearing in elongate spikes. It is found along streams and valleys in deserts, particularly in damp or saline soil, and grows to about 7 meter (23 feet). It is distinguished from the very similar Honey Mesquite (Prosopis glandulosa) by its tightly twisted seedpods (legumes) which very much resemble turned screws. This morphology may have been an evolutionary defense against seed predators such as bean weevils (Bruchinae). Like Honey Mesquite, these seed pods are valued by wildlife and were eaten by native people.

Plant type

Tree

Size

10 - 33 ft Tall
20 ft Wide

Form

Upright

Growth rate

Fast

Dormancy

Winter Deciduous

Calscape icon
Color

Yellow

Flowering season

Spring, Winter

Special uses

Bank stabilization, Deer resistant

Sun

Full Sun

Water

Low

Summer irrigation

Max 1x / month once established

Ease of care

Easy

Cold tolerance

Tolerates cold to 15° F

Soil drainage

Fast

Soil description

Typically sandy or decomposed granite.
Soil PH: 6.0 - 8.0

Propagation

For propagating by seed: No treatment. Seedlings damp-off very readily. Some lots may need hot water or scarification.

Sunset Zones

7, 8*, 9*, 10, 11, 12*, 13*, 14*, 15, 16, 18, 19*, 20*, 21*, 22, 23

Site type

Creek, river bottoms, sandy or gravelly of the desert

Plant communities

Creosote Bush Scrub, Wetland-Riparian

Use with other desert trees and shrubs such as Desert Agave (Agave deserti), Elephant Tree (Bursera microphylla), Desert Lavender (Condea emoryi), Brittlebush (Encelia farinosa or actonii), Barrel Cactus (Ferocactus cylindraceus), Ocotillo (Fouquieria splendens), Chuparosa (Justicia californica), Beavertail Cactus (Opuntia basilaris), Palo Verde (Parkinsonia spp.), Smoketree (Psorothamnus spinosus), Joshua Tree (Yucca brevifolia), and Mojave Yucca (Yucca shidigera).

Bats
Caterpillars
Butterflies

Butterflies and moths supported

1 confirmed and 19 likely

Confirmed Likely

Ceraunus Blue

Hemiargus ceraunus

Palmer's Metalmark

Apodemia palmerii

Black Witch

Ascalapha odorata