While its horticultural characteristics and taxonomy remain the subject of sometimes heated discussion, Thornless Hybrid Mesquites are among the most popular and widely used trees in the desert landscape palette. It is not difficult to understand its popularity among landscape professionals given the trees’ qualities.

As the name indicates, the trees are thornless, making them ideal for landscape applications from re-vegetation of disturbed desert sites to streetscapes, park plantings and commercial and residential landscapes. The form and texture of Thornless Hybrids blend almost seamlessly with surrounding native Sonoran desert trees and shrubs. They are easily incorporated into urban landscapes and are increasingly being used in more formal or traditional landscape designs. They are used as theme trees along streets and commercial projects, as screens, wind breaks or barrier plantings, as transition trees back to native species in re-vegetation projects or any landscape applications where ample shade is desired. At maturity, Mesquites can be up to 30 feet tall and as wide with symmetrical, dome- shaped, spreading canopies. The foliage is lacy and fern-like with compound leaves consisting of anywhere from 20 to 40 leaflets. Cold hardy to 10 to 15 degrees F, they can be planted throughout most regions of the desert southwest.

Trees are semi-deciduous losing only a portion of the leaves in warmer winter locations. Leaves remaining through the winter are shed rapidly in spring just prior to bud break. In late spring Mesquites produce yellow-green, unremarkable, catkin-like flowers. By early summer curved and sometimes curled tan to brown seed pods mature and are shed. With supplemental irrigation and fertilization, Thornless Hybrids grow at a rapid rate. Mature, established Mesquite trees can be naturalized to survive on annual rainfall in desert soils with higher water holding capacity. Trees are most lush and exhibit best growth and appearance with irrigation during the hot, dry summer months.

The shade produced by Thornless Hybrid Mesquites can range from filtered to quite dense. Shade is a welcome addition to all deserts landscapes but may inhibit the growth and flower production of under-story plantings. Carefully consider the ultimate shade that can be produced by these trees and the impact of shade on the growth and flowering of under-story plants and turf.

Thornless Hybrid Mesquites will tolerate an array of soil types and growing conditions from harsh, full sun to shady bosque or grove-like plantings. The first 2 to 3 years following transplanting are critical in establishing a well distributed root system. In landscape settings where water and nitrogen are usually abundant, Mesquites can produce large dense leaf canopies from limited root systems. These trees are often easily damaged or completely uprooted by the high winds associated with the summer rainy season.

Wind damage and uprooting are the products of poor pruning and staking practices and improper irrigation and should not be considered as inherent, unavoidable horticultural shortcomings of Thornless Hybrids. Making trees "seek out" water and nutrients, by appropriate arrangement of irrigation emitters, fosters the development of a more dispersed root system and re duces the risk of wind throw. Pruning to remove about 20% of the canopy every 3 to 4 weeks during the growing season helps promote root development that is proportional to the shoot growth of young trees. Removing more than 20% of the canopy can inhibit rooting and encourage undesired re-growth made up of dense flushes of branches and leaves. Selective pruning should be used to foster the development of a symmetrical canopy with well spaced branches. Stake trees only when absolutely necessary and then only briefly. A low- breaking, upright tree occupies no more room than a standard-trunked specimen yet retains the natural wind resistance of trees found growing native in desert settings.