Summer in the American Southwest is brutal: months of triple-digit heat, rain that evaporates in mid-air and scorching winds. It's no wonder that most plants wither in the long slog from June to November.
But roses, which have an undeserved reputation for being delicate and demanding, are an exception. Although the flowers are fragile, the bushes are remarkably tough. With the right rose in the right location, and as little as an hour of care a year—excluding watering—roses not only survive but thrive in a desert climate. Here's what it takes:
Water often and deep. Irrigation is crucial in regions where the average annual rainfall is measured in thimblefuls, but the amount of water varies with the season and your soil.
"If there's a problem with your roses, nine times out of 10, it's related to water," says Marylou Coffman, a Gilbert, Ariz. rosarian and All-America Rose Selection Committee judge. Coffman recommends watering at least three times a week during the hottest months, using a minimum of three to four gallons per plant each time. Potted roses need water every day when the temperature soars. "It's almost impossible to overwater in summer," she says.
Use plenty of mulch. Mulching is essential for keeping roots cool, controlling weeds and conserving moisture in arid soils. Coffman suggests applying mulch after you prune roses in January and maintaining a four-inch layer year-round. Compost, ground western cedar, pine needles and hay all work well. As mulch decays, it enriches the soil and improves drainage—both real problems in the Southwest—without any hard labor on your part.
Give some shade to these sun-lovers. Roses can take the heat; it's intense sunlight that stresses them most. In the Southwest many roses do best with some afternoon shade in summer, but hosing down your plants at least two to three times a week is the next best thing, according to master gardener Vicky Donalson. "The spray cools the foliage, increases humidity around the plants and helps control mites and aphids," she says.
Feed your roses. Roses don't just like to eat, they like to eat well. Though they can live without fertilizer even in nutrient-poor soil, regular feeding gives them glossy foliage and richly colored, beautifully textured blooms. Many rose experts recommend time-release fertilizers. Keep in mind that these formulas break down more quickly as temperatures rise, so a three-month fertilizer may last just six weeks in the desert.
Another option is a standard rose food. Apply it every four weeks through May. Then cut back to half strength, or stop fertilizing entirely until September to give plants a rest in the hottest months.
If, like many gardeners, you want to avoid synthetic fertilizers, try this all-natural blend, courtesy of Steve Schneider, an ARS consulting rosarian in Las Vegas: 1 cup bone meal, 1 cup cottonseed meal, 1/2 cup blood meal, 1/2 cup fish meal and 1/2 cup Epsom salts per plant. Scratch the mixture lightly into the soil around your roses, and, as with all dry fertilizers, water thoroughly before and after you apply it. Use it about twice a year—after winter pruning and before the fall bloom.
The secret weapon. Rosarians have an almost mystical regard for alfalfa, a modest but splendid substance that provides far more bang for the buck than any other fertilizer or soil amendment. Alfalfa stimulates basal breaks—new growth from the bud union that ensures a vigorous plant with beautiful blooms. Some people scatter alfalfa pellets around the base of each bush; others mix alfalfa meal with their regular fertilizer. But Schneider swears by alfalfa tea: Fill a 30-gallon trash can with water; add 10 big handfuls of alfalfa meal, cover and let marinate for four days before pouring on the roots. He says the extra work—and slight barnyard smell—is worth it, producing the healthiest and most vigorous plants he's had in years.
Patience. Growing roses in the Southwest requires patience. At the height of summer, your roses may not bloom at all and when they do, the flowers are apt to be disappointing—small and pale with crispy leaves. Horticulturally, summer is the desert's winter—a period of near-dormancy in which your only goal is to keep plants alive. But with the first cool days of late fall, Southwest roses put forth an astonishing, making-up-for-lost-time display. And if, by chance, a rose does succumb in August, Schneider takes the long view. "Remember," he says, "it's only a plant."
The Top 10. Many of the roses that flourish in temperate climates do well in the desert, too. But for beauty, ease-of-care and a proven track record in the Southwest, experts especially like these cultivars:
'Julia Child' (Coffman says this new, butter-yellow floribunda bloomed in the AARS Arizona test garden all summer without fading.)
'Rainbow Knock Out'
'Sally Holmes' (Schneider loves this prolific climber, with its salmon-to-white nosegays reaching 10" to 12" in diameter.)
—Linda Rath is a freelance writer who lives and tries to garden in suburban Phoenix.