What is Arizona Ash?

Arizona ash, or Fraxinus velutina, is a softwood, deciduous tree that is hardy in mild to tropical climates. Other common names for this tree include velvet ash, desert ash tree, leatherleaf ash and smooth ash, and in some places, it is known as the Modesto ash, Toumey ash or Fresno ash. The Arizona ash is a very fast-growing tree, typically reaching a height of about 40 feet (12 m), although some might reach 80 feet (24 m). The tree, native to Arizona and southwestern New Mexico in the United States, is characterized by its velvety fuzz on young branches and leaves. Perfect for xeriscaping, the Arizona ash tolerates drought conditions and provides exceptional shade for hot desert locations.

Grown from seed, the Arizona ash reaches maturity quickly, towering over most desert ranch buildings and spreading a profuse network of intertwined branches. As one of the most popular desert garden trees, the Arizona ash is grown for its very fast growth and lush, thick canopy. Velvety shoots grow to produce five to seven compound leaves, and its tiny, inconspicuous flowers appear in early spring. In autumn, the deciduous Arizona ash turns yellow and drops its overflowing abundance of leaves.

Horticulturalist Calvin R. Finch nicknamed the Arizona ash "Arizona trash" because the tree is so short-lived and plagued with problems. Fast-growing softwood trees such as the Arizona ash build a shallow network of roots in the hard soil and therefore are unable to withstand severe monsoon winds. Shallow roots permeate the surface of the ground, destroying sidewalks, curbs and home foundations.

Thickly growing branches grow too quickly, promoting fungal diseases such as anthracnose and frustrating gardeners who are unable to keep up with the constant need for pruning. Insect enemies of the Arizona ash, such as borers, feed on the tender vascular system of the tree, causing sudden death. Branches might drop unexpectedly from pest infestation or limb failure, causing property damage and hazardous conditions.

Despite the seeming multitude of problems that plague the Arizona ash, the tree is widely grown and coveted for its ability to provide quick shade and beautiful green foliage for gardens. Arizona ash is hardy to minus-10 degrees Fahrenheit (minus-23 degrees Celsius), tolerates extreme heat and drought exceptionally well and thrives in full desert sun without complaints. With tender care and constant pruning, the Arizona ash can provide decades of relief from the harsh desert environment.