Screwbean mesquite (Prosopis pubescens) is a shrub that grows 25 feet tall and wide. It has an open vase-shaped form with fern-like foliage. Older branches have flaky bark that peels off easily. Bright yellow catkin-type flowers bloom in late spring to early summer. The seed pods resemble tightly wound springs or screws, which is how the plant got its common name. Screwbean mesquites are extremely drought-tolerant and grow slowly during dry periods. They grow faster when they receive regular watering. Prune in late winter before new growth appears.
Use hand pruners for limbs less than ½ inch in diameter and lopping shears for limbs up to 1 inch in diameter. Cut larger limbs with a pruning saw. Make cuts just above a joint or bud at a 30-degree angle.
Remove dead and diseased limbs at ground level. Symptoms of disease include dead or dying leaves (out of season), splits in the bark or wood, and oozing patches on the bark.
Prune out crossed or bent limbs, as well as damaged limbs that are broken or scarred.
Thin out weak older growth--limbs that have lighter colored foliage or fewer leaves than the other limbs--at ground level. This will encourage healthy new growth.
Trim limbs that extend beyond the main body of the plant or that obstruct passageways back to the first joint or bud within the body of the plant.