Currently, Desert Willow trees with their fragrant, orchid-like flowers are filling the Santa Cruz Valley with soft, spring color. Not a true willow, Chilopsis linearis is a member of the family of blooming plants that includes Yellowbells and certain trumpet vines.
With their desert-adapted characteristics, these trees survive where actual willows could not. Desert Willow tap roots reach downward 50 feet or more in search of needed water.
Their leaves have a waxy coating that limits evaporation. During long periods of extreme heat and drought, leaves will fall and the trees become dormant. When rains begin, new leaves are produced and photosynthesis re-starts.
Long slender leaves make this deciduous tree appear much like a traditional willow. However, the real show comes from the bell-shaped flowers with their open, flared ends with ruffled edges. Blossom colors range from white to lavender to pink and deep burgundy. Although attracting hummingbirds, these handsome flowers are pollinated primarily by large, noisy, black carpenter bees.
After flowering, most Desert Willows produce slender seed pods 4 to 12 inches long. These may hang on to the branches all winter. Numerous papery, winged seeds are released from the pods and easily germinate.
With regular watering, Desert Willows grow rapidly up to 3 feet a year for several years before slowing down. Most will mature around 20 feet high with a 15 feet spread.
With rainfall alone Desert Willows will survive, but for the best appearance should be watered once or twice a month during hot summers. Deep irrigation with a soaker hose is an effective and simple way to water trees. Mature Desert Willows do not require fertilizer and are not susceptible to pests or disease.
In nature, these trees have a shrubby growth habit with basal suckers and branches reaching the ground, making them a perfect rest stop for wildlife. In the landscape, the canopy is more often lifted to create tree form.
Because of its unique branch structure, haphazard pruning can lead to extensive suckering and an uncharacteristic shape. Occasional trimming is recommended while the tree is without foliage so results can better be seen.
If your landscape has an area of reflected intense heat, the Desert Willow may be the perfect tree. They may be planted any time from containers into full sun or partial shade. Best establishment seems to take place when they are in leaf when planted. Although tolerant of most soil types, Desert Willows do need excellent drainage.
For a desirable accent tree with graceful foliage and gorgeous flowers, consider the Desert Willow for your landscape.
Mary Kidnocker is a University of Arizona Master Gardener who lives in Green Valley. Her articles are featured weekly.