Prosopis velutina 'AZT' ('AZT' Native Mesquite)
Foliage: Deciduous
Mature Height: 25’ - 40’
Mature Width: 20’ - 40’
Growth Rate: Moderate
Hardiness: 0 degrees F
Exposure: Full Sun
Leaf Color: Dark Green
Shade: Filtered to Dense
Flower Color: Cream
Flower Shape: Fuzzy Spike
Flower Season: Mid-Spring
Thorns: Yes
Propagation Method: Cutting
Sizes Available: #25, #45, & 48"
There is much disagreement within the botanical and horticultural literature as to what constitutes an authentic Native Mesquite. Some suggest that the tree is, in reality, Prosopis velutina while others support claims that it is Prosopis juliflora. In contrast, the literature on the genus Prosopis generally agrees that nearly all the “species” within this genus freely hybridize and that many documented species are likely hybrids that can attribute their distinction to the area or region where they were studied and described. Scientific controversies notwithstanding Native Mesquite, however one chooses to define it, is among the most commonly found trees in the Sonoran desert. We began developing Prosopis velutina (juliflora) ‘AZT™’, Native Mesquite, in part, to try to address some of this confusion and to bring greater uniformity in growth and form to this remarkable, uniquely Sonoran desert tree. Additionally, this ‘AZT™’ variety is less attractive to vector insects (aphids, thrip, whiteflies or psyllids) reducing or completely eliminating the need for seasonal pesticide applications to control these pests.
Traditionally Native Mesquites are distributed throughout Central and Southern Arizona, West Coast of Mexico and the West Indies. In the wild it grows along stream beds, in washes, on slopes and mesas where deep soils are found and on plains. Some Native Mesquites are distinguished from the other species discussed by the short dense hairs that cover nearly the entire plant including the seed pods. This fuzzy appearance has led some to refer to this species as Velvet Mesquite. In the landscape, trees grow best in well draining soils. Maturing trees can be naturalized to survive on rainfall alone but look more lush with deep, monthly summer irrigations. In the landscape, trees grow at a moderate rate and can reach a height of 40' and spread 20 to 40' with trunk diameters of up to 3 feet. More mature specimens have dark, shaggy bark and feathery, soft, gray-green foliage that provides welcome filtered shade in summer. Native mesquites tolerate lawn planting but shade from these trees at maturity may inhibit growth of summer lawns and understory plantings. In nature the trees grow as multiple trunk specimens, nursery cultivated trees are typically grown in multi-trunk forms. Cream colored, cylindrical flowers appear by mid-spring and tan seed pods are shed in summer. In informal desert designs, Native Mesquites can be used as a theme tree, as individual specimen at entry monuments, around golf course tee boxes, lining the fairway, backdrops of greens or as the center piece of desert scenes. This beautiful Native Mesquite brings a feeling of the Sonoran Desert into any landscape design.
Prosopis velutina (juliflora) ‘AZT™’ we are so confident of the quality, we put our name on it.
Variety 'AZT™':
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 further evaluation. Only the best of these trees are then used in our cloning production and are then designated Variety 'AZT™'. Since no one single selection of any desert tree species is best adapted to all landscape applications, we continually search for new additions to our Variety 'AZT™'.
An additional characteristic that sets ‘AZT™’ selection of clone and seed trees apart from the competition is the trees health vigorous root system, the result of AZT’s Root Management Program.
Prosopis velutina (juliflora) 'AZT™' is propagated and available exclusively from Arid Zone Trees.
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 Prosopis varieties. 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 encourage roots to "seek out" water and nutrients. Frequent watering is needed to promote good terminal growth on newly planted trees. Irrigation emitter arrangement along with other information on irrigations practices for desert trees can be found at Irrigation Practices for Desert Trees.
Prune as needed to reinforce the structure and form of the tree. Periodic thinning is the most desirable method of pruning. 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. Avoid hedging or heading back desert species, as this will only stimulate excessive branching. 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. Always use clean, sharp tools that are cleaned regularly in a 10% solution of bleach. For detail pruning guide see Pruning Desert Trees.
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.
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.