Screwbean Mesquite (Pubescens)

The Screwbean Mesquite (Pubescens) is generally described as a perennial tree or shrub. This is native to the U.S. (United States) has its most active growth period in the spring and summer and fall . The Screwbean Mesquite (Pubescens) has green foliage and inconspicuous flowers, with an abuncance of conspicuous brown fruits or seeds. The greatest bloom is usually observed in the early spring, with fruit and seed production starting in the summer and continuing until summer. Leaves are not retained year to year. The Screwbean Mesquite (Pubescens) has a moderate life span relative to most other plant species and a rapid growth rate. At maturity, the typical Screwbean Mesquite (Pubescens) will reach up to 25 feet high, with a maximum height at 20 years of 10 feet.

The Screwbean Mesquite (Pubescens) is easily found in nurseries, garden stores and other plant dealers and distributors. It can be propagated by bare root, container, cuttings, seed. It has a none ability to spread through seed production and the seedlings have high vigor. Note that cold stratification is not required for seed germination and the plant cannot survive exposure to temperatures below -3°F. has medium tolerance to drought and restricted water conditions.

Uses of : Landscaping, Medicinal, Culinary, etc.

Ethnobotanic: Various kinds of mesquite trees provided staple foods for indigenous people of southern California, the Great Basin and the Southwest and their seed pods are still highly relished today. Screwbean pods were eaten by the Maricopa, Hualapai, Pima, Cahuilla, Luiseno, Mohave, Panamint and Death Valley Shoshone, the Chemehuevi, Ute, Gosiute, and Southern Paiute groups as far east as the edge of the Colorado Plateau. The pods can be harvested at two different times, in the spring, while still green and consumed raw as snacks or in the late summer when the pods are ripe. If collected in the late summer, traditionally they were placed in bedrock mortars or tree-stump mortars and pounded to fine flour using stone pestles. The meal was set out to dry and then stored in baskets in grass- or bark-lined pits in rock-shelters or caves. Basketfuls of meal were also kept in indigenous homes and added to cooked agave or made into small cakes. Another way to prepare the pods was to cook the screwbeans in pits covered with earth and left to stand three or four days, and then spread to dry. The mass was then pounded in a mortar and the fine meal eaten as pinole.

The plant was also important medicinally. The Pima used the bark of the root of the screwbean as a dressing for wounds. There were two ways to prepare the dressing and then these concoctions were applied at different times. First, the bark was boiled and the liquid applied to the fresh wound. Second, the bark was ground up in a mortar, dried, and again pounded into a fine meal in a metate and this powder was applied to the wound after a few days. The Pima also used a tea made from the roots of screwbean to regulate a woman's menstrual troubles. A gummy exudate sometimes found on the bark was gathered and soaked in water and the Moapa Paiute used the resulting liquid as eyewash. The large branches were used in construction such as fencing and binding for large granary baskets made by the Pima, and the Cahuilla sometimes used the smaller branches for bows. The mescal cutter, a long pole that was used by the Cahuilla to sever agave leaves was made of screwbean. The root wood is good for firewood for cooking.

Wildlife: Screwbean is an important tree to wildlife. The seeds are eaten by jackrabbits, Gambel quail, songbirds, various small mammals, and domestic livestock. Western chipmunks, ground squirrels, pocket mice, and various species of kangaroo and wood rats consume the foliage. Different birds also nest in the tree's canopy. The early spring growth also furnishes food for domestic livestock.

General Characteristics

General: Pea Family (Fabaceae). This upright, deciduous shrub or tree reaches up to 10 m in height. It has gnarled, shaggy multiple trunks and forms a round spreading crown. The ascending branches have pairs of spines that are 4-12 mm long. The compound leaves are hairy and measure 2-6 cm long, with as many as eighteen tiny leaflets per leaf. The leaflets are arranged on the two-branched prongs of a Y-shaped leaf stem. The yellow flowers have fused petals and are in a raceme, 4-8 cm. and spikelike. The dark tan fruit is tightly coiled, 3-5 cm and appears in pod clusters of 2 to 15. The pods are persistent and often exit holes can be seen on each pod, evidence that tiny bruchid beetles have deposited their nurseries inside. The tan seeds are very small, about 3 mm. The pollen of screwbean is toxic to honeybees. The plants crown-sprout after injury to the trunk or after cutting.

Required Growing Conditions

For current distribution, please consult the Plant Profile page for this species on the PLANTS Web site. This plant is uncommon in California, found mainly in the San Bernardino Mountains and the desert. It is more common in the southwestern United States in southern Nevada, southwestern Utah, southern Arizona and New Mexico, western Texas and northern Mexico in Baja California, Sonora, and Chihuahua. It is found in creek and river bottoms, sandy/gravely washes, or ravines from 100-1300 m.

\* MERGEFORMATINET Steve Hurst USDA ARS Systematic Botany @ PLANTS

Cultivation and Care

Gather the seed pods and take the seeds out of the pods. Some seed lots may need scarification. Otherwise the seeds require no treatment. Plant the seeds in a well-drained soil in deep pots. Sprinkle soil on top of the seeds and place one-quarter inch gravel on top of the soil. The seeds should be spaced one-half inch apart and the pots placed in partial shade. The seeds germinate best at warm soil and air temperatures. Water the pots right away. Keep the pots moist if the rains are insufficient. As soon as the plants form one true leaf, transplant one plant per pot and water. Keep the pots damp. Plant each plant out in the ground the following winter when dormant in full sun and well-drained soil. Protect the plants from wildlife. Water the plants and keep them damp if the rains are insufficient. Also do some watering in summer. Continue to water throughout the life of the plant once in awhile. Mesquite should be lightly damp all summer long.



General Upkeep and Control

Screwbean can tolerate pruning and can be shaped into a small tree with an exposed trunk or let grown naturally with the branches touching the ground. PRSE2"Black cherry is sometimes grown in even-aged management –– clearcutting or shelterwood cuts are used, depending on the availability of soil-stored seed. Where deer populations are high, successful regeneration may require that larger seedlings be so abundant that deer cannot eat them all. Because it is shallow-rooted and has a tendency to overtop its associates in mixed stands, black cherry is susceptible to wind throw. Best results in establishing black cherry on reclamation or rehabilitation sites are by planting 1-year or older nursery grown seedlings. Direct seeding has generally been unsuccessful.

The thin bark of black cherry makes it highly susceptible to girdling, and it is usually killed or top-killed by fires of moderate severity. As fire severity increases, the percentage of tree-sized individuals killed also increases. When aboveground portions are killed by fire, black cherry sprouts prolifically from the root crown or stump. This vegetative reproduction, however, depletes carbohydrate reserves and leaves plants in a weakened condition. Quickly repeated fires would probably kill any seedlings and saplings that survived the first fire by resprouting.

Pests and Potential Problems The eastern tent caterpillar and the cherry scallop shell moth defoliate black cherry and can cause growth loss and mortality. The fungal disease “black knot” is common on black cherry – it causes elongated, rough, black swellings on the twigs, branches, and trunk. "

Plant Basics
Growth Rate Rapid
General Type Tree, Shrub
Growth Period Spring, Summer, Fall
Growth Duration Perennial
Lifespan Moderate
Plant Nativity Native to U.S.
Commercial Availability Routinely Available
Physical Characteristics
Bloom Period Early Spring
Displays Fall Colors No
Shape/Growth Form Single Stem
Drought Tolerance Medium
Shade Tolerance Intermediate
Height When Mature 25
Vegetative Spread None
Flower Conspicuousness Yes
Fruit/Seed Abundance High
Fruit/Seed Seasonality Summer Summer
Seed Spread Rate None
Gardening Characteristics
Propagations (Ways to Grow) Bare Root, Container, Cuttings, Seed
Moisture Requirements Medium
Cold Stratification Required No
Minimum Temperature -3
Soil Depth for Roots 24
Toxic to Nearby Plants No
Toxic to Livestock No
After-Harvest Resprout Ability Yes
Responds to Coppicing Yes
Growth Requirements
pH Range 7.5–9 pH
Precipitation Range 6–6 inches/yr
Planting Density 50–1200 indiv./acre
Soil Textures Coarse, Fine, Medium
Soil Depth for Roots 24
Minimum Frost-Free Days 200 day(s)
Salinity Tolerance High
CaCO3 Tolerance Medium
Sustainability & Use
Leaf Retention No
Palatability High
Fire Resistant No
Causes Livestock Bloating None

Source: USDA, NRCS, PLANTS Database,
National Plant Data Center, Baton Rouge, LA 70874-4490 USA