Arid landscaping, or xeriscaping (from the Greek word xeros, meaning dry), is the integration of practicality and beauty in drought-prone public and private gardens. Xeriscaping is part of a larger trend among environmentalist gardeners to incorporate native rather than imported species within local ecosystems.
In drought-prone areas like California, where water conservation is imperative and lawns and flower gardens are at risk, gardeners have taken several steps to cope with drought . A 20-by-40-ft (6-by-12 m) green lawn requires about 2,500 gal (9,475 l) of water a month, enough for a four-member family for 10 days. Some arid landscapers eliminate lawns altogether and replace them with flagstone or concrete walkways; others aerate the soil or cut the grass higher for greater water retention. More popular is replacing imported grasses with native grasses, already adapted to the local climate , and letting them grow without being cut.
Some big trees, such as oak, do better in drought than others, such as birches or magnolias. To save big trees that are expensive and important providers of shade, some gardeners place "soaker" hoses, in which water flows out through holes in the length of the hose in concentric circles at the base of trees and water them deeply once or twice a season.
More commonly, arid landscapers replace water-loving shrubs and trees with those best adapted to drought conditions. These include some herbs, such as rosemary, thyme, and lavender, and shrubs like the silvery santolina, which are important in color composition of gardens.
Other plants that grow well in semi-arid and arid conditions are legumes (Leguminosae), poppies (Papaveraceae), daisies (Compositae), black-eyed susans (Rudbeckia fulgida ), goldenrod (Solidago ), honeysuckle (Lonicera ), sunflowers (Helianthus ), daylilies (Hemerocallis ), and eucalyptus. Generally, drought-resistant plants have silvery leaves that reflect sunlight (argentea ); hairy (tomentosum ) or stiff haired (hirsuta ) leaves that help retain moisture; long narrow leaves (angustifolia ), threadlike leaves (filimentosa ), and aromatic leaves (aromatica ) that provide a moisture-protecting haze in heat.
Drip irrigation , hoses with small regular holes, whose amount is regulated by timers, is the most efficient xeriscape watering technique. Mulching with dead leaves, pine bark, straw, and other organic matter helps retain soil moisture. Soil types are a critical part of arid landscaping: one inch (2.5 cm) of water, for example, will penetrate 6–8 in (15– 20 cm) into loam (a sand, peat, and clay mixture), but only 4–5 in (10–13 cm) into dense clay.
Arid landscapers monitor plant health and soil dryness only when necessary, often in the early morning or in the evening to avoid evaporation by the sun. Recycling "gray" water, runoff from household sinks and washing machines, is best if the water is used quickly before bacteria collects and if laundry detergents are biodegradable . Arid landscapers, using native and drought-resistant plant species in conjunction with stone and concrete walkways and mulch , create gardens that are not only aesthetically pleasing but ecologically healthy.
[Stephanie Ocko ]
Ball, K. Xeriscape Programs for Water Utilities. Denver: American Water Works Association, 1990.
Ball, K., and G. O. Robinette. "The Water-Saving Garden Landscape." Country Journal (September/October 1990): 62–69.