Foliage: Evergreen to Semi-Deciduous

Mature Height: 15’ - 40’

Mature Width: 15’ - 40’

Growth Rate: Slow to Moderate

Hardiness: 20 degrees F

Exposure: Full Sun

Leaf Color: Gray-Green

Shade: Filtered

Flower Color:  Purple

Flower Shape: Pea Shaped Petals

Flower Season: Late Spring to Summer

Thorns: Yes

Propagation Method: Cloning

Sizes Available: 24”, 36”, 48"

Olneya tesota ‘AZT’, Desert Ironwood. The characteristics that sets this ‘AZT’clone apart from seed selections are faster growth with a v-shaped, upright form and larger leaflets while retaining the graceful, chalk-gray trunks and branches.

Ironwoods take their name from the dense, dark and heavy wood the tree produces. The wood is prized for carving and as firewood. It is native to the southwestern US and northwestern Mexico. In native settings it is typically found on rocky, well draining slopes and plains at elevations below 2500 feet. Foliage is gray green and semi-evergreen with leaves dropped in response to long drought or freezing temperatures. Trees are hardy to 20 degrees F but can sustain foliage and small twig damage at 25 degrees F. Mature trunks and branches are pale gray/white while immature wood is pale green and armed with many, sharp, curved thorns.

The natural growth habit is multiple trunks with branches extending to the ground. Natural forms are excellent in plantings that transition landscaped areas back to undisturbed desert or when used as a security planting. To create a more cultivated appearance trees will require selective pruning. Trees produce clusters of small  purple flowers from April to June. Mature trees can grow to 30' by 40' but typically are 15' to 20' tall and as wide.

Ironwoods are highly adapted to the hottest environments in the Sonoran desert. Trees will not thrive in lawns or when mixed with landscape plants that require regular winter irrigation or summer irrigation more frequent than once a month. No single factor contributes to the death of Ironwoods more than does over irrigation.

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 evaluation.  Only the best of these trees are then placed in cloning production and are designated Variety 'AZT'.  Since no one single selection of any desert tree specie is best adapted to all landscape applications, we continually search for new additions to our Variety 'AZT'.

Olneya tesota 'AZT' is propagated and available exclusively from Arid Zone Trees. 

Cultural Practices:

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.  Irrigation emitter arrangement along with other information on irrigations practices for desert trees can be found at www.aridzonetrees.com and click on the FAQ link.

 Prune as needed to reinforce the structure and form of the tree. Periodic thinning is the most desirable method of pruning. Avoid hedging or heading back desert species, as this will only stimulate excessive branching. Do not remove more than 30% of the canopy during the summer as this can lead to sunburn injuries that can later be invaded by wood boring insects. Always use clean, sharp tools that are cleaned regularly in a 10% solution of bleach. For detail pruning guide see www.aridzonetrees.com and click on the FAQ interactive button.

 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.