Much of coastal and southern California has a Mediterranean climate, which is characterized by cooler, wetter winters and hotter, drier summers. Only drought-resistant plant species can survive without irrigation in this type of climate. Turf grass, for example, most certainly will not survive such dry summers without irrigation. And yet in 2015, four years into the latest California drought, some homeowners in southern California continue to grow turf grass and water their lawns. See also: Drought; Irrigation (agriculture); Lawn and turf grasses; Plant-water relations
The U.S. Environmental Protection Agency (EPA) estimates that in dry climates as much as 60 percent of a household’s water use is for landscaping. In southern California, cities are trying to conserve water by offering homeowners monetary incentives to remove their lawns. As a result, commercial services have sprung up that replace homeowners’ lawns with rocks, gravel, mulch, drought-tolerant plants, and even synthetic grass, should they choose. Often, the municipal incentives cover the costs of the landscaping projects. See also: Water conservation
According to landscape architects and designers, drought-tolerant landscaping, also known as xeriscaping, is an attractive alternative to turf grass that uses much less water and requires less maintenance. By using drought-tolerant and native plants that have evolved to withstand a dry season, these landscapes mimic regional ecosystems. Plants that can handle southern California's dry summers include sycamores, native oaks, bay laurel, lavender, rosemary, oreganos, thymes, verbenas, succulents, and ornamental grasses, to name just a few sturdy and colorful examples. For functional and aesthetic purposes, landscape architects incorporate into the design gravel and stepping-stone pathways, boulders, and decorative urns and barrels. See also: Lamiales; Landscape architecture; Landscape ecology; Laurales; Oak; Oregano; Ornamental plants; Plant geography; Rosemary; Sycamore; Thyme
Drought-tolerant plants still require a certain amount of irrigation, or at least some hand watering in the summer, particularly during a drought. To conserve water, landscape architects recommend collecting stormwater runoff and "building sweat" from air conditioners, as well as designing the landscape to reduce stormwater runoff. Mulch may also be used to allow water to drain into the soil, to keep the soil cool and moist, and to prevent weeds (which compete with landscaped plants for water) from growing. See also: Arboriculture; Weeds