Arid Zone Trees makes selections from thousands of trees propagated from seed.  Only individual trees having the most desirable physical qualities (branching habits, leaf color, leaf canopy, and flower color) and sound horticultural characteristics (rooting, cold hardiness and growth rate) are selected for further study.  These trees are then cloned (vegetatively propagated) and planted at our nursery for evaluation.  The best of these trees are placed in our cloning production and are designated Variety ‘AZT™’.  Since no single selection of any desert tree species is best adapted to all landscape applications, we continually search for new additions to our Variety ‘AZT™’. Our Prosopis seedless hybrid ‘AZT™’ was selected and placed in production through this process.

 Prosopis seedless hybrid 'AZT™', ‘AZT™’ Seedless Hybrid Mesquite:

 These trees exhibit a uniform appearance, upright growth and strong branch angles. Leaflets give the canopy a lush dark green look. The characteristics that set this ‘AZT™’ clone variety apart from all other seed or cloned selections is that even though it produces flowers it does not set seed pods (is seedless), uniform upright growth, synchronous bud break and, with sound horticultural practices, root mass growth that is in proportion to canopy growth. This tree is slow growing. The Prosopis seedless hybrid ‘AZT™” produce no seed, making them ideal for landscape applications from re-vegetation of disturbed desert sites to streetscapes, park plantings and commercial and residential landscapes.  Trees are 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 this Mesquites produces a few yellow-green, unremarkable, catkin-like flowers that are sterile. By early summer other varieties of Mesquites will produce seed pods and shed them to the ground while Prosopis seedless hybrid ‘AZT™’ is a no mess, clean non-fruit bearing tree.  The shade produced by Prosopis seedless hybrid ‘AZT™’ can range from filtered to quite dense. Shade is a welcome addition to all desert 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.

Above are the ‘AZT™’ thornless on the left and the ‘AZT™’ Seedless on the right.

 Prosopis hybrids:

 While its horticultural characteristics and taxonomy remains the subject of sometimes heated discussion, Prosopis hybrids 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. The form and texture of Prosopis hybrids blend almost seamlessly with surrounding native Sonoran desert trees and shrubs. 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.

Prosopis hybrids 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. 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. 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.

Cultural Practices:

Periodically insect pests can be a problem on some desert trees.  On young trees, insect infestation can slow typical seasonal growth. Inspect trees during the growing season for common garden sucking insects such as aphids, thrip, whiteflies or psyllids. During dry months, (May and June) in dusty conditions, spider mites can appear. Monitor for infestation and apply controls as needed. Spray applications of water or water and Safer Soap give short-term control (3 to 7 days) for small insect population. For heavy infestation or longer control use federally registered insecticides. A contact insecticide application will kill existing adults. An application with a systemic soil drench will provide 8 to 12 weeks control for any post application insect hatchings or migration of insects. Before using pesticide for the first time or on new plants or cultivar, treat a few plants and check for phytotoxicty.  Always read label and follow label instruction before using pesticides. For pesticide control recommendations contact a licensed pest control advisor.

 Irrigation emitter arrangement, planting details, pruning and insect information for desert trees can be found at FAQ.