The Desert Willow - March 3, 1999
Jeff Schalau, County Director, Agent, Agriculture & Natural Resources
Arizona Cooperative Extension, Yavapai County
An excellent water conserving patio tree for the Verde Valley is the Desert Willow (Chilopsis linearis). This tree is not a willow at all, but a close relative of the catalpa tree and a member of the trumpet vine family (Bignoniaceae). This deciduous, native tree/shrub can be found along dry washes and seasonal creeks in desert, chaparral, and grassland habitats between 1,500 and 5,000 foot elevations. It is hardy to 10 degrees F or lower and requires little water once established. However, it will grow faster if given additional water during dry hot periods.
The desert willow is very graceful with an airy, open canopy. Hence, it does not make dense shade but has a filmy quality. This makes it a good choice in areas where security may be a concern. In the wild, they can grow to 20 feet tall by 20 feet wide. With irrigation, they can get slightly larger. Desert willows are usually multi-trunked, but they can be pruned to a single trunk if desired.
The long, narrow, curving leaves are between 5 and 12 inches long and 1/4 to 1 inch wide. They look very graceful but have a surprisingly tough, leathery texture. Desert willows are best known for their showy flowers. These appear in clusters on branch tips from late spring to early summer and can vary in color from white to deep purple. Normally, they are off-white to pale lavender with yellow spots or stripes in the throat of the trumpet-shaped, orchid-like blossoms. The blooming season is usually in late spring or early summer, but with some additional care they can bloom through September. In addition, the flowers have a sweet fragrance that attracts bees and hummingbirds.
All bad jokes aside, the desert willow is a truly exceptional tree. Once the flowers have bloomed, long, narrow seedpods are formed. These persist on the tree through the winter and split open to release hundreds of fuzzy seeds. The seeds are viable and may germinate in a moist seedbed. I suppose, if there is a downside to desert willow, it is the pods and seeds. Excessively orderly gardeners may think them untidy. If you are of this persuasion, then plant a course ground cover underneath the tree.
Being a native, the desert willow has relatively few pests or diseases. Aphids may appear on the new leaves and blossoms in the spring. These can be treated with a high pressure spray. If they are really bad, then mix 1 TBSP dish detergent with a gallon of water and spray it on. Better yet, let the natural predators and hummingbirds eat them. Cicadas can also cause twig damage. Just think of this as natural pruning and enjoy their sweet music (hmmmm).
Nurseries have selected individuals from the wild, cloned them, and market these cultivars as named varieties that have showier flowers or smaller stature. Some of the newer varieties are "Barranco", "Burgundy Lace", "White Star", "Pink Star", "Lucretia Hamilton", "Warren Jones", and "Lois Adams". There is also a Chitalpa (Chitalpa tashkentensis): a hybrid between the desert willow and the catalpa (Catalpa bignonoides). It was bred in Tashkent, Uzbekistan.
If I have failed to sell you on this tree's merits, then call or visit the Cottonwood Cooperative Extension office and ask for a copy of "Drought Tolerant Trees for the Verde Valley". This University of Arizona publication has several other trees that are well suited to the local area. It's a great time of year to plant trees.
The University of Arizona Cooperative Extension has publications and information on composting and cover crops. If you have other gardening questions, call the Master Gardener line in the Cottonwood office at 646-9113 or E-mail us at firstname.lastname@example.org and be sure to include your address and phone number.
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