Xeriscaping

The principles of gardening with less water

January 28, 2014

In areas of the country where drought is measured in years—years in which winter rain did not replenish the reservoirs—xeriscaping is becoming a way of life in the garden. This method depends on basic water-saving principles, such as increasing soil organic matter content and mulching, as well as on using native plants and reducing areas of water-guzzling lawn grass.

A xeriscape (from the Greek xeros, meaning dry) is a water-saving garden designed for a dry region. Xeriscaping is especially useful in the western half of North America, where little rain falls in summer and gardeners depend heavily on irrigation. Savvy gardeners have been incorporating some of these principles in their own gardens for years. The idea gained more widespread notice, and an official name, in 1981, when the Denver Water Department developed the concept and the policy of xeriscaping as a way to deal with the West’s chronic water shortages. Even Eastern gardeners in areas of relatively dependable rainfall can benefit through an offshoot called mesiscaping, or planning a garden that is only moderate in water use.

Water-Saving Principles

Xeriscapes do not have to be desert gardens. Xeriscapers emphasize that these gardens can be lush and colorful. Gardeners in any region can use the seven principles of xeriscaping in designing or rejuvenating a garden.

1. Incorporate water savings into your planning and design. Map your yard’s microclimates and soil types, paying special attention to the places that stay moist longest and those that dry out fastest or are most difficult to irrigate. In your design, plan zones of high, moderate, and low water use, based on your map. Group plants with similar water needs in these zones. Put your high-water-use plants where you’ll appreciate them most, for example, near an entryway or patio.

2. Improve your soil or select adapted plants. For plants with high or moderate water needs, dig the soil deeply and add plenty of organic matter. Many drought-tolerant plants prefer unimproved soil. Group these and leave their soil unamended. See the Soil entry for more information on improving your soil organically.

3. Limit the area in lawn. Lawns are high-water-use areas. Although some grasses tolerate drought better than others, all lawn grasses need similar amounts of water to look good and stay healthy.

Design your lawn to be a small oasis of green. Xeriscape experts calculate that the average single-family garden needs no more than 800 square feet of lawn. Site your lawn next to a patio or driveway, so activities can spill over from one into the other.

Keep edges rounded, and avoid irregularly shaped areas or narrow strips of lawn. Irregular shapes and peninsulas have more edge area that will abut pathways or areas of bare soil that heat up quickly, and the heat will promote faster moisture loss from the lawn. Plant lawns only on level ground to reduce runoff. Select grasses that are drought tolerant and adapted to your region and soil type.

4. Use mulches. Mulch any unplanted soil areas with 2 to 3 inches of organic mulch or a thick mulch of gravel or stone. Either can be laid over weed-resistant landscape fabric. The little rain that does fall will be able to soak through these porous mulches. Keep overall design in mind: You don’t want such a large area of mulch that your garden is no longer a green landscape.

Photo: (cc) teofilo/flickr

5. Irrigate efficiently. If you water by hand, test your soil before you water. Water established plants only if the soil is dry several inches below the surface. Better yet, construct a water-efficient irrigation system. Plan it to allow different watering schedules for areas of high, moderate, and low water use. Lawns require sprinklers, but water other plants with soaker hoses or drip irrigation.

6. Use plants that don’t demand as much water. There is no one best list of plants for a xeriscape. Plant lists for Denver, for instance, include native Colorado maples (Acer spp.), but California is so dry that no maples are recommended. Another plant, Catalina lilac (Ceanothus arboreus), is an excellent choice for California gardens but would be killed by Denver’s higher summer rainfall and colder winters. Xeriscapers often turn to plants native to a particular region or to regions with similar climates and soils. Many familiar landscape plants are also adaptable. Water even drought-tolerant plants until well established.

7. Maintain the garden in ways that save water. Tend your garden well, fertilizing and pruning when needed, and checking for pests. Inspect your irrigation system frequently for leaks or other malfunctions. Adjust the timing so that the system releases more or less water as needed during drier and wetter seasons of the year.

Planning a Xeriscape

Learn more about xeriscaping by visiting a demonstration garden in your area. Denver built the first of such gardens. To find out the location of the one nearest you, call your local water department or botanical garden.

When you’re ready to select plants, learn as much as you can about the ones you’re considering. Watching a plant grow for a year is the best way to judge, but you can also get recommendations from nurseries. Plant lists in books and water department publications can help you decide if a plant is suited to your region. Books and other publications will provide details such as height, bloom season, and any potential problems. Another easy way to choose is to observe your neighborhood and note plants that thrive without irrigation.

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