How to Take Care of Arizona Ash Trees
The Arizona ash tree (Fraxinus velutina), also known as a velvet ash, is a drought-tolerant, deciduous shade tree common in states like California and Texas. This is a high-maintenance tree that requires plenty of pruning.
The Arizona ash tree is winter hardy in USDA zones 6 to 8.
Arizona Ash Tree Identification
Native to North America, specifically the American Southwest with a range that extends into Mexico, the Arizona ash tree has a fast growth rate. A full grown Arizona ash tree is usually around 40 feet tall. Its large crown makes it a good shade tree. It is also used as a street tree.
The Arizona ash tree has dark green leaves that are compound, meaning that they are made up of small leaflets, and bark that is gray in color. This species produces yellow flowers in the winter, but they are not very noticeable.
The Modesto cultivar (Fraxinus velutina 'Modesto,' zones 6 to 8) is a more compact tree than the species plant. The leaves of the Modesto ash are a bright green compared to the species Arizona ash. This cultivar dazzles with golden yellow fall color.
Arizona Ash Tree Care
The Arizona ash tree grows best in full sun, which means at least six hours of direct sunlight a day. However, the bark of trees that have few leaves may burn if exposed to too much sun.
Arizona ash trees grow best in full sun and can handle some drought.
One of the advantages of Arizona ash trees is that they can grow in many types of soil, whether alkaline or acidic, and can be drought resistant in certain conditions—though these trees do appreciate consistent watering.
Arizona Ash Tree Problems
Arizona ash trees have a short lifespan, partly because of trunks that tend to break and pest infestations. Let’s look at some of these common Arizona ash tree problems.
If you decide to plant an Arizona ash tree, be prepared to do plenty of pruning. This is because this species of tree tends to produce multiple trunks on the same spot on the main trunk, leading to weak branches that are prone to breakage.
Yearly pruning during an Arizona ash tree's first 15 years of life is key to helping this species develop a strong trunk and branches that won't break easily.
For the first 15 years of an Arizona ash tree's life, pruning is therefore necessary to remove some of these excess trunks and create a strong, stable structure. Unlike some other young trees, Arizona ash trees do not need to be staked.
Like other species of ash tree in the genus Fraxinus, the Arizona ash tree is vulnerable to the emerald ash borer (Agrilus planipennis), a pest native to Asia that was first detected in North America in 2002 and can kill a tree within a few years.
This pest has driven other species of ash trees in the U.S. to the verge of extinction. Anyone growing ash trees in their gardens should monitor for signs of this pest, which often spreads on infested firewood.
- Bag up all leaves and twigs from the Arizona ash to prevent the spread of disease to other trees in the areas. Promptly dispose of the bags.
Since beginning her career as a professional journalist in 2007, Nathalie Alonso has covered a myriad of topics, including arts, culture and travel, for newspapers and magazines in New York City. She holds a B.A. in American Studies from Columbia University and lives in Queens with her two cats.