Site and soil. "I would rather rely on nature for rainfall and not worry about watering," says Carol O'Meara, horticulture extension agent in Boulder, Colorado. To do that, you must maximize the benefits of every raindrop by allowing as little as possible to leave the site and by putting plants that need the most water where they're most likely to get it. "Look at how water moves naturally through your landscape," O'Meara says. Note areas that receive more water than others; the space around downspouts, for example. Then cluster plants that like moist soil in those areas. Put drought-tolerant plants in the drier places.
You want the soil to hold moisture but still drain well, and adding organic matter is the surest way to achieve this. Do a simple drainage test: Dig a 12-inch-deep hole and fill it with water. If the water either drains instantly or sits for 30 minutes or more, it's a sign that your soil is too porous, or not porous enough. Mix in compost or finely shredded leaves.
Condition ready. "Plants don't save water, people do," proclaims a xeriscaping bulletin from the University of Georgia. Save by choosing healthy plants that are adapted to your climate and soil type, and growing them in their preferred conditions alongside plants with similar needs. The reason? The right plant in the right place needs less care overall, and that includes supplemental water.
Botanic gardens, garden clubs, and your extension service can all steer you to plants that are right for your region. And don't forget your nursery. "Local garden centers are very in tune with what does well in their area," O'Meara says.
Water when necessary. The ideal "water less" landscape gets by on rainfall alone, but that's not always possible. Even when you do need to water, however, following xeriscaping principles can reduce your outdoor consumption by as much as 50 percent.
Most perennials need supplemental water only in the three months after planting. Water trees and shrubs through the first growing season or until they become established.
Drip-irrigation systems and hand watering are the most efficient hydration methods. Avoid overhead sprinklers; they waste water by directing it where plants aren't (enabling weed-seed germination) and also wet the foliage, inviting disease.
Mulch always. All this work is for naught if you don't apply mulch around your plantings. Blanket the soil with a 2-to-3-inch layer of organic mulch, such as shredded leaves, bark nuggets, or compost, to slow the evaporation of water in the soil. Xeriscaping doesn't mean giving up plants you want to grow. It means making every drop count.
Life on the Dry Side
Although many kinds of plants flourish in a water-wise landscape, a tough bunch weather hard times better than others. Those touted as "drought-tolerant" have adaptations that help them store water during long dry spells. For your hottest, driest spots, look for these indicators of drought-tolerance:
Fuzzy leaves prevent water loss thanks to a dense mat of fine hairs. Example: lamb's ears (Stachys)
Gray leaves reflect sunlight, reducing water loss from the leaf surface. Russian sage (Perovskia atriplicifolia)
Large, fleshy roots are belowground water-storage vessels. Adam's needle (Yucca)
Succulent leaves are aboveground water-storage vessels. Stonecrop (Sedum)
Waxy leaves are coated with a dense barrier that prevents water loss. Rosemary (Rosemarinus officinalis)