Watering every day during drought conditions is neither prudent nor necessary. Instead, water deeply once or twice per week. In sandy soil, you can let a hose run for an hour or more. In clay soils, you may need to break the watering session in half. Water for 30 minutes and then stop for a few hours to allow the soil to absorb the water before watering again. The practice of watering deeply encourages roses to form deep roots that can access moisture well below the soil surface. Slowly reduce your watering frequency to once per week, followed by once every 10 days. Increase the watering time slightly, as well.
How you water roses during a drought is as important as how much you water them. Use soaker hoses, drip systems or hoses, rather than overhead sprinklers. These systems deliver water right to the soil so that less is lost to evaporation. These watering devices also keep roses healthier by keeping leaves dry. Wet leaves often spread disease. Water roses early in the morning rather than during the heat of the day.
The environmental conditions you grow your roses in also play a role in water conservation. Plant roses in a protected location away from harsh, hot winds. A sunny location surrounded by shrubs is ideal. Plant a few ground cover plants under the roses, which can help reduce surface evaporation. A 2- to 3-inch layer of wood chip mulch also helps conserve moisture, while reducing weed growth. Avoid overpruning roses. When roses are heavily pruned to produce blooms, they lack the foliage that protects them from intense heat. They tend to dry out more quickly and need more water. Prune only to remove dead canes and control size.
Finicky hybrid tea roses seem to be falling out of favor, as gardeners seek rose varieties that need less maintenance and water. Old-fashioned shrub roses as well as trailing roses are the descendents of wild roses, which often grew in poor soil and dry conditions. These roses are naturally drought-tolerant and can adapt to a variety of growing conditions, including partial shade. "Therese Bugnet" (Rosa "Therese Bugnet") is native to Japan, Siberia and Alaska. It tolerates cold, as well as hot, dry conditions, and produces pinkish-purple blooms. "Martha's Vineyard" (Rosa "Martha's Vineyard") is another drought-tolerant shrub rose worth trying. It produces clusters of tiny pink flowers.