Mesquite is the most common shrub/small tree of the Desert Southwest. Like many members of the Legume Family (called Fabaceae these days), mesquite restores nitrogen to the soil. There are 3 common species of mesquite: Honey Mesquite (Prosopis glandulosa), Screwbean Mesquite (Prosopis pubescens ) and Velvet Mesquite (Prosopis velutina).
All 3 are deciduous and have characteristic bean pods which have long been used by humans, wildlife and livestock as a food source. It is estimated that over 75% of a Coyote’s diet in late summer is mesquite beans.
Native Americans relied on the mesquite pod as a dietary staple from which they made tea, syrup and a ground meal called pinole. They also used used the bark for basketry, fabrics and medicine. A favorite of bees and other insects, mesquite flowers produce a fragrant honey.
The taproots, which can be larger than the trunk, are often dug up for firewood. Next to Ironwood, mesquite is the best firewood of the desert, because it burns slowly and is smokeless. The wood is also used for fenceposts, tool handles and to create aromatic charcoal for barbecuing.
Cattlemen regard mesquite as range weeds and eradicate them, but much of the invasion of mesquite into former grasslands, where it did not grow a century ago, is due to overgrazing.
Sonoran, Mojave and Chihuahuan deserts from western Texas, west to extreme southwestern Utah, southeastern California and adjoining Mexico.
Alongside desert washes and streams, plains and hillsides, often in thickets below 5,500 feet.
Honey Mesquite (Prosopis glandulosa)
Honey Mesquite is a shrub or small tree characterized by 8-inch, bean-like pods and 3-inc spines occurring at large nodes on branches. It reaches a height of 20 feet; the trunk may be up to 12 inches in diameter.
Honey Mesquite has smooth, brown bark that roughens with age. Narrow, bipinnately compound leaves 2 to 3 inches long are sharply pointed. They are yellowish green in color with oblong leaflets 1/8″ wide and 1 1/4″ long.
Honey Mesquite blooms in May displaying 1/4-inch long fragrant, creamy yellow flowers in narrow 3-inch clusters. The fruit is a flat, narrow, yellow-green pod up to 8 inches long and ending in a point.
Screwbean Mesquite (Prosopis pubescens)
The Screwbean Mesquite is a shrub or small tree characterized by 2-inch, screw-like pods and spiny, twisted branches. It reaches a height of 20 feet; the trunk may be up to 8 inches in diameter.
The Screwbean Mesquite has light-brown to reddish, smooth bark that separates into long, shaggy strips. Narrow, bipinnately compound leaves 2 to 3 inches long are sharply pointed. They are dull green in color and slightly hairy containing 5 to 8 pairs of oblong leaflets 1/8″ wide and 3/8″ long.
The Screwbean Mesquite blooms May through August displaying many crowded, 2-inch clusters of 3/8-inch light yellow flowers. The fruit is a hard, 2-inch, spiraled, brown-to-yellow pod with sweet pulp.
Velvet Mesquite (Prosopis velutina)
Velvet Mesquite is a larger shrub or medium-size tree characterized by straight, 2-inch spines on the branches. Often growing in dense thickets, it is larger than the other species, reaching a height of 30 feet; the trunk may be up to 24 inches in diameter.
Velvet Mesquite has dark-brown, smooth bark that separates into long, shaggy strips. Narrow, bipinnately compound leaves 2 to 3 inches long are sharply pointed. They are dull green in color with gray hairs.
Velvet Mesquite blooms in April, and sometimes again in August, displaying displaying small, fragrant, greenish yellow flowers in slender, cylindrical spikes up to 4 inches long. The fruit is a slender, brown pod up to 8 inches long.
Medical studies of mesquite and other desert foods, said that despite its sweetness, mesquite flour (made by grinding whole pods) “is extremely effective in controlling blood sugar levels” in people with diabetes. The sweetness comes from fructose, which the body can process without insulin. In addition, soluble fibers, such as galactomannin gum, in the seeds and pods slow absorbtion of nutrients, resulting in a flattened blood sugar curve, unlike the peaks that follow consumption of wheat flour, corn meal and other common staples.
“The gel-forming fiber allows foods to be slowly digested and absorbed over a four- to six-hour period, rather than in one or two hours, which produces a rapid rise in blood sugar,”
Mesquite trees usually in most of their range they are the size of a shrub. Older trees can reach a height of 20 to 30 ft. They have narrow, compound leaves 50 to 75 mm (2 to 3 inches) long that are sharply pointed.
Mesquite is an extremely hardy, drought-tolerant plant because it can draw water from the water table through its long taproot (recorded at up to 190 ft in depth). However, it can also use water in the upper part of the ground, depending upon availability. The tree can easily and rapidly switch from utilizing one water source to the other.
The plant’s bud regeneration zone can extend down to 6 inches (150 mm) below ground level. The tree can regenerate from a piece of root left in the soil.
New growth of mesquite has tough, needle-sharp thorns up to 3 inches long.
Mesquite trees furnish shade and wildlife habitat where other trees will not grow. They will often be found in alkaline soils near water holes.
Although a single flower of the blossom is only a few millimeters long, they are clustered into a yellow creamy blossom attracting many different types of pollenators.
The various types of mesquite can be identified by the seed pods. Screwbean mesquite pods curl around back onto themselves and are the easiest to identify. Honeybean and velvet mesquite are a little harder to differentiate. While both trees’ seed pods are long and legumous, the velvet mesquite pods have a slight velvety appearance and feel.