M E E T   T H E   N A T I V E S

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Desert Willow Indigenous Imposter

by Cathy Rymer,
Master Gardener, Certified Arborist, Water Conservation Specialist, Town of Gilbert

BOTANICAL NAME
Chilopsis linearis

COMMON NAMES
Desert Willow, Desert Catalpa, Flowering Willow, False Willow, Jano

Although the long, narrow leaves of this plant are reminiscent of willows, this imposter isn't a willow at all. Rather, it is a close relative of the catalpa tree, and a member of the trumpet vine family (Bignoniaceae), which also includes the genus Tecoma. Desert Willow is drought-tolerant, and can be found growing naturally along our ephemeral streambeds or washes, where it offers natural protection against flood and erosion damage. From May through October colorful, lightly scented tubular flowers appear, making this attractive tree a popular choice for local urban landscaping.

Desert Willow grows as a deciduous large shrub or small tree that can reach 25 feet in height and 20 feet in width. Even without its familiar green foliage during the colder months, the silhouette of Chilopsis linearis is unmistakable on the western horizon in early evening. Its branches seem to zigzag their way to the edges of the leaf canopy, while long, narrow, papery pods hang decoratively and release their treasured seeds to hungry birds throughout the winter season.



CLASSIFICATION & RANGE
This strikingly beautiful plant primarily occupies dry washes, intermittent streams, and other watercourses of the damp canyon lands of deserts and mountain foothills between 1,500 and 5,000 feet in elevation throughout much of the southwestern United States and into Mexico. It is classed as a phreatophyte, and is an indicator that during part of the year water is not too far below the surface. One of the few trees in this region that is not a legume, it reminds us of the Sonoran Desert's tropical heritage.

A long-lived component of somewhat-stable desert wash communities, Desert Willows often establish themselves in freshly deposited channel sediments following seasonal water runoff. Under this scenario, plants may trap sediments as they develop, leading to the formation of islands within the channel.

In its natural setting, common associates of Desert Willow include blue palo verde (Cercidium floridum), desert ironwood (Olneya tesota), catclaw acacia (Acacia greggii), smoketree (Dalea spinosa), mesquites (Prosopis spp.), desert broom (Baccharis sarothroides), netleaf hackberry (Celtis reticulata), and littleleaf sumac (Rhus microphylla).

DESCRIPTION
The natural form of this tree is multi-trunked with a graceful appearance. The long, narrow, straight or curving leaves are simple, linear, alternate, and range between 5 and 12 inches long and 1/4 to 1 inch wide with a surprisingly tough, leathery texture. The foliage on some trees can be aromatic with a slightly medicinal fragrance. The attractive white, burgundy, or pink trumpet-shaped, orchid-like flowers have distinctive yellow throats that serve as visual nectar guides for pollinators. Blooms appear in terminal clusters from May through October. The resulting seedpods are dehiscent, 4 to 9in long, and cling persistently on branches throughout winter. The bark of Chilopsis linearis is smooth when young, but develops rough fissures with age. Prominent lenticels are noticeable on new growth. Plants drop leaves in late fall following the first hard frost, yet they are cold hardy to 0 degrees Fahrenheit.

PROPAGATION & CARE
Adaptable to most soils as long as drainage is good, this tree prefers full sun but will tolerate partial shade. Established plants are considered drought-tolerant, requiring only the deep, infrequent irrigations recommended for most desert-adapted trees. Little maintenance is required for this tree, but minor selective pruning may be appropriate if a more tree-like form is desired. Fallen leaves and seedpods will blend into a coarse groundcover, eliminating the need to rake or remove them.

Easily propagated from seed, Desert Willow can also be grown vegetatively from cuttings and is a fast grower in urban landscapes. Individuals have been selected from the wild, cross pollinated with other specimens, cloned, and marketed with characteristics such as specific flower color or growth habit. Some of the newer varieties are "Rio Salado," "Lucretia Hamilton," "Warren Jones," and "Lois Adams." Russian hybridizers from Tashkent, Uzbekistan crossed the catalpa (Catalpa bignonoides) with the Desert Willow, which resulted in the Chitalpa (Chitalpa tashkentensis), a tree that produces no seeds.



LANDSCAPE USES
In hot, dry areas the attractive form, willow-like leaves, and beautiful blooms of Chilopsis linearis are a welcome sight. It is a must-have for luring hummingbirds into a landscape, and even small native birds such as verdins will search out the nectar-producing flowers (although they tend to pierce the flower at the base as a shortcut).

When placed on the south, east or west sides of homes, Desert Willows provide shade in the summer while allowing ambient heating in the winter. You can lend contrast to this tree's deciduous winter appearance by planting evergreen shrubs and groundcovers nearby. It is one of the few native trees that will tolerate growing in a lawn area even with year-round irrigation and maintenance. Planted in groups, the Desert Willow can be used as a screen or windbreak. It also provides shelter for nesting birds.

HISTORY & FOLKLORE
The strong yet flexible wood of Desert Willow was used by Native Americans to craft their hunting bows. The wood has also been used by the Pima to construct houses, thatch roofs, and in the making of baskets to store mesquite beans, acorns and other foods. The fibrous bark was used to make nets and fabrics.

It is important to wildlife because it provides nesting sites and cover. Animals such as deer and birds also consume the leaves, fruit and the flower's nectar. Birds eat the white-fringed seeds, and the nectar is used by bees for honey.

MEDICINAL USES
The Desert Willow's flowers, leaves and bark have all been used in hot poultices and as a soothing tea for coughs. Other known uses were as treatments to guard against yeast infections, athlete's foot and as first aid for scrapes and scratches. Tea (from the flowers) produces a natural anti-oxidant, which promotes cardiovascular health and regulates glucose metabolism.



By including one of these trees in your landscape, you can have color and fragrance; attract native birds and other wildlife; and have shade and/or sun in places where it's needed. If you're looking for a specific flower color, shop at local nurseries when the trees are in bloom. Desert Willow trees propagated from seed can vary in their flower production and color intensity. Named cultivars that are propagated vegetatively will be consistent in these characteristics. Look for a tree with good vigor and a profusion of blooms in the color you like.

Watch for Desert Willow gracing the cover of the new Landscape Plants for the Arizona Desert brochure featuring more than 200 low-water use plants, each with a full-color photo and description. Contact your city's water conservation office or the Arizona Municipal Water Users Association at http://www.amwua.org or call 602-248-8482.

REFERENCES:
Medicinal Plants of the Southwest, New Mexico State University. http://medplant.nmsu.edu/chilopsis.htm

Arid Zone Trees. "Desert Willow." http://www.aridzonetrees.com/aztimes/aztimes95/sep95vol2-9.htm

A Field Guide to the Plants of Arizona, Anne Orth Epple, 1995, Falcon Press

Trees and Shrubs of the Southwestern Deserts, Lyman Benson & Robert Darrow, 1945, University of Arizona Press

Maricopa County Master Gardener Volunteer Information
Last Updated January 23, 2004
Author: Lucy K. Bradley, Extension Agent Urban Horticulture, University of Arizona Cooperative Extension, Maricopa County
© 1997 The University of Arizona, College of Agriculture and Life Sciences, Cooperative Extension in Maricopa County
Comments to Maricopa-hort@ag.arizona.edu 4341 E. Broadway Road, Phoenix, AZ 85040,
Voice: (602) 470-8086 ext. 301, Fax (602) 470-8092