Southwest BY JUDY MIELKE / Scottsdale, Arizona, Zone 9
FALL COMES LATE to the desert. Not until November do the daytime temperatures reliably stay below 80°F. And the nighttime lows rarely dip below 45°F, so the cold-induced foliage color exhibited in northern regions is largely absent here. The best fall color occurs in riparian areas, where the cottonwoods and willows create golden threads through the desert. Although these large-scale, thirsty trees are not practical for most gardens, other plants can fill the need for a splash of fall foliage color.
The greatest impact comes from trees. Chinese pistache (Pistacia chinensis) turns orange to red before dropping its foot-long compound leaves. This native of China can reach 30 feet tall or more, and about as wide. Arizona ash (Fraxinus velutina) is similar to Chinese pistache in size and form. Its foliage turns bright yellow in fall. Another yellow-foliaged tree, thornless honey locust (Gleditsia triacanthos f. inermis), has a more vertical habit, to about 35 feet tall and 20 feet wide. These three tree species will tolerate some drought but do best with regular irrigation, about once a week during the summer. Desert willow (Chilopsis linearis) may turn golden yellow in the fall, depending on temperatures. A pretty show of pink to lavender trumpet-shaped flowers through the summer helps compensate for the sometimes mediocre fall display. Native to the southwestern United States and northern Mexico, desert willow is very drought tolerant; established trees can get by with irrigation once or twice a month during the warm season.
If your garden doesn’t have room for a full-size tree, consider pomegranate (Punica granatum; pictured), a large shrub to small tree that has orange-red, apple-size fruits and yellow foliage in the fall. ‘Wonderful’ is the selection most commonly grown for fruit. Pomegranate grows in a vase shape to 12 feet tall and about as wide. When grown for ornamental purposes, pomegranates require a deep soaking every other week through the summer; for the best fruit production you will need to increase the irrigation frequency to at least once a week.
An alternative to trees for providing both shade and fall color is California wild grape (Vitis californica). ‘Roger’s Red’ is an especially colorful selection that has burgundy foliage touched with orange. A vigorous grower, ‘Roger’s Red’ prefers full sun and irrigation once a week during the summer. The small grapes, though edible, are best appreciated by the birds.
The cooler temperatures of fall bring on a flush of bloom to accompany the colorful foliage. The yellow blooms of cascalote (Caesalpinia cacalaco), a small evergreen tree, begin opening in fall and continue through the winter. Turpentine bush (Ericameria laricifolia), black dalea (Dalea frutescens), and chuparosa (Justicia spicigera) display flowers of yellow, purple, and red, respectively, joining a host of other plants that provide fall color.
In some ways, fall in the desert is like spring elsewhere—plants that have endured the summer in a semidormant state seem to catch their breath and get a second wind, making the garden a pleasant and colorful place this time of year. H
Landscape Plants for Dry Regions by Warren Jones and Charles Sacamano Perseus Publishing, 2000
Two legendary figures in southwestern horticulture, Jones and Sacamano teamed up to write this essential reference for southwestern gardeners. Photos and descriptions of over 600 species of trees, shrubs, groundcovers, and succulents make this a must-have for the reference shelf.
NURSERIES OF NOTE
Whether you’re looking for a hard-to-find native plant or something more ordinary, like a pony pak of cilantro, Shady Way Gardens offers a wonderful selection of plants. Cacti and succulents are a specialty. A bonus is the free monthly newsletter. Bits and Briefs, written by nursery owners Sarah and Paul McCombs.
Shady Way Gardens 566 West Superstition Boulevard Apache Junction, AZ 85220 480-288-9655