Prosopis seedless hybrid 'AZT' ('AZT' Seedless Hybrid Mesquites)
Foliage: Deciduous
Mature Height: 20’ - 40’
Mature Width: 20’ - 40’
Growth Rate: Moderate
Hardiness: 15 degrees F
Exposure: Full Sun
Leaf Color: Dark Green
Shade: Dense
Flower Color: Cream
Flower Shape: Fuzzy Spike
Flower Season: Late Spring
Thorns: Barb
Propagation Method: Cloning
Sizes Available: #25, #45, & 48"
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 green look. The characteristics that set this ‘AZT™’ clone variety apart from all other seed or cloned selections is the very limited number of flowers and their associated pollen, the complete absence of seedpods (is seedless), uniform upright growth, synchronous bud break and, with sound horticultural practices, root mass growth that is in proportion to canopy growth. The Prosopis seedless hybrid ‘AZT™’ its upright growth habit requires less pruning than commercially produced Prosopis species.
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™’.
Prosopis seedless hybrid ‘AZT™’ is among the more 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. This tree produces no seed pods, making them ideal for landscape applications from pedestrian patio and walkways to streetscapes, park plantings, commercial and residential landscapes. The form and texture of Prosopis seedless hybrid ‘AZT™’ 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 and seed pod litter is a concern. 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. Watch for insect infestation on terminal buds after bud break and treat as needed. In late spring this Mesquites produces a few yellow-green, unremarkable, catkin-like flowers that do not produce seed pods. 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.
Prosopis hybrids:
Prosopis seedless hybrid ‘AZT™’ 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. With supplemental irrigation and fertilization, Prosopis seedless hybrid ‘AZT™’ grows at a slower rate than other commercially produced Mesquite trees. 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. Due to this trees slower growth, these trees are less inclined to damaged or uprooting by the high winds associated with the summer rainy season.
Cultural Practices:
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 desert trees. Plant “Root Management” trees and at installation inspect and shave ¼- ½” of the rootball sides to lessen wind thrown up-rooting of trees. Foster the development of a more dispersed root system and reduce the risk of wind throw by arranging irrigation emitters at varying distances from the trunk to beyond the future tree canopy encouraging roots to "seek out" water and nutrients. Frequent watering is needed to promote good terminal growth on newly planted trees. Once roots begin to radiate out into the native soil remove watering by root flair area. Pruning to remove about 20% of the canopy 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, lead to sunburn injuries that can later be invaded by wood boring insects, and encourage undesired re-growth made up of dense flushes of branches and leaves. Selective pruning should be used to promote the development of a symmetrical canopy with well spaced branches. Use tree stakes only when absolutely necessary and then only briefly. Select low-breaking, upright trees as they occupy no more space than a single-trunk specimen yet retain the natural wind resistance of trees found growing native in desert settings.
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 phytotoxicity. 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.
The information provided here was gathered from research literature published by the University of Arizona, other professional landscape and horticulture organizations and our experience at Arid Zone Trees. Always consult local landscape experts for recommendations for your specific area.