WEF's membership newsletter covers current Federation activities, Member Association news, and items of concern to the water quality field. WEF Highlights is your source for the most up-to-the-minute WEF news and member information.

July / August 2009, Vol. 46, No. 6

Top Story

Waterwise Gardening During the Summer
Water utilities promote Xeriscape gardening in arid regions

In 1981, when a group of Denver Water employees gathered to determine how to landscape their headquarters so the plants wouldn’t wither in the dry climate, they did not expect their solution to sweep the nation. The employees created the term Xeriscape™, formed by a combination of the Greek word xeros, which means dry, and landscape, and defined it as a method of landscaping that promotes water conservation. The utility decided to make its solution of Xeriscape into a public outreach program.

“We launched this whole program … basically to solve one of our problems, which we knew was a somewhat similar problem for other Denverites,” said Elizabeth Gardener, suburban conservation coordinator at Denver Water.

Denver Water's Xeriscape demonstration garden is open for public viewing. Photo courtesy of Tim LaPan, landscape architect, Denver Water. Click for larger image.

Xeriscape relies on seven landscaping principles of planning and design, soil improvements, efficient irrigation, zoning of plants, mulching, turf alternatives, and appropriate maintenance. 

“You can do Xeriscaping anywhere, because [it] is just a set of seven principles,” Gardener said. “They are principles of good landscape design.” People only need to find a list of local native or adaptable plants suitable for the average rainfall in their area. Gardener stressed that landscaping is very important to be done regionally, taking into account the local geography, climate, and local situations.

The concept, now regularly used by different groups, from nonprofits to government agencies, has been the central topic of many books and Web sites, as well as various public outreach programs in arid regions.
Over the years, as each summer season brings sweltering conditions and drought, water utilities search for ways to promote water conservation. Many have decided to promote Xeriscaping. According to the U.S. Environmental Protection Agency’s WaterSense Web site, water used for irrigation across the nation is estimated to total more than 26.5 billion L/d (7 billion gal/d), accounting for almost one-third of all residential water use.
Water utilities across the U.S. Southwest have installed demonstration Xeriscape gardens to encourage water conservation in their areas. “We as public servants can help make our own buildings and grounds more sustainable,” Gardener said.
Denver Water created its demonstration garden in 1981 at its administrative building. It is open to the public every day during business hours, plants are labeled, and tours are provided to groups on request. The garden originally consisted of 0.13 ha (0.33 ac) but has grown to 0.4 ha (1 ac) with more than 200 species of water-saving plants, including trees, shrubs, perennials, and grasses.
One of the main concepts of Xeriscape is that the plants do not have to consist only of cacti; there are often many plants that prefer the local climate, and the gardens can be green and lush with flowering plants. Even in the eastern portion of Colorado that receives 330 to 381 mm (13 to 15 in.) of precipitation a year and less during drought seasons, Denver Water has identified 480 different plants that can be put in a Xeriscape garden. 

The images demonstrate elements of a landscape that has not been Xeriscaped (left) and a landscape that has been Xeriscaped (right). Graphics courtesy of the U.S. Environmental Protection Agency from the report Water Efficient Landscaping: Preventing Pollution and Using Resources Wisely. Click for larger images.

Tim LaPan, landscape architect for Denver Water, explained that people can choose the amount of water that they want to use in their gardens. Gardens can be “extremely xeric” and only need watering to become established and then no longer need supplemental watering, relying solely on the natural precipitation.
Denver Water’s Xeriscape public outreach also has included landscape seminars, brochures of different landscaping plans, books with information on local Xeriscape plants, outreach television and radio ads, and educational videos, Gardener said.
In addition to demonstration gardens, landscaping classes and seminars, and public outreach, water utilities also can be found to offer Xeriscape rebates. The Albuquerque (N.M.) Bernalillo County Water Utility provides a Xeriscape rebate to those that replace their high-water-use plants with water-saving plants. Single-family residential rebates offered are $8.07/m² ($0.75/ft²) credit on water bills, for a minimum of 46 m² (500 ft²) and up to 1161 m² (12,500 ft²). The Southern Nevada Water Authority offers property owners up to $16.15/m² ($1.50/ft²) for grass removed and replaced with water-efficient landscape. The Aurora (Colo.) Municipal Center is offering $10.76/m² ($1/ft²) for turf that is replaced with low-water-use plants for a maximum of 929 m² (10,000 ft²) for residential areas and 2322 m² (25,000 ft²) for commercial properties. The municipal center’s water conservation division also provides free design consultations for residents that complete a two-part course on Xeriscaping.
In 2001, a coalition of groups from Texas worked together to use the Xeriscape principles and offer another level of service. The North Central Texas Council of Governments (NCTCOG; Arlington), Tarrant County Health Department, Texas Extension Service, Tarrant Regional Water District, Texas Parks and Wildlife, and Weston Gardens joined to create the Texas SmartScape® program “to promote education on pollution prevention through efficient and effective water use,” according to the Web site.
Two areas have joined the program, North Central Texas and West Texas, to provide design, care, and plant search tools. These tools originally were available on CD but turned into an interactive Web site in 2003, according to Erin Blackman, NCTCOG environment and development planner.
“We’re hoping to eventually get other regions in the state [to participate],” Blackman said. For the two participating areas, citizens can get area-specific information on how to design and care for a “waterwise” garden, more than 200 plants that are native or adapted to the local climate, design tools for a variety of water-saving techniques, local environmental landscaping events, and resources, including local professionals that can assist with garden design and implementation and a garden gallery with pictures of local water-saving gardens.
“In this region, the population is expected to grow significantly, so our water supply is a big concern,” Blackman said. “Choosing plants that can stand the rains in the spring but also the heat of the summer is important.”

The Upper Trinity Regional Water District (UTRWD; Lewisville, Texas) demonstration garden was planted approximately 8 years ago and now covers 2.5-ha (6-ac). Photo courtesy of UTRWD. Click for larger image.

Upper Trinity Regional Water District (UTRWD; Lewisville, Texas) is one of the sponsors of the Texas SmartScape® Web site and one of the demonstration gardens listed under resources for the North Central Texas area. Approximately 8 years ago, the water district began a program to promote watershed protection that centers on a 2.5-ha (6-ac) demonstration garden. 

“We really wanted it to demonstrate what home gardeners can do,” said Tom Taylor, executive director of UTRWD. “[Proper landscaping] will make a lot of difference both in terms of conserving water and … protecting water quality,” he said. Since no pesticides are used, this prevents these types of chemicals from getting into the water supply.
“We illustrate all kinds of landscape,” Taylor said. The water district has created a Japanese-style garden, a Hill Country-style (Texas-style) garden, and an English-style garden. The water district also has created wetland and native-prairie areas. It also landscaped a patio and parking lot, and demonstrates to visitors elements of mulching, Taylor explained. 

The UTRWD demonstration garden is designed to be functional and extends through the parking lot and a patio used by employees and visitors. Photo courtesy of UTRWD. Click for larger image.

“We teach how to do it, not just the selection of plants,” Taylor said. Plants in the garden are labeled, and the water district provides a list of plants in their gardens. The district opens up its gardens to group tours and offers volunteer opportunities and training events for the local master gardener and master naturalist programs, Taylor added. In addition, the garden area is practical, with the wetlands handling drainage, the patio area and parking lot frequently used by employees and visitors, and the remaining landscape surrounding the water treatment plant. “Most of it is very functional,” Taylor said. “It’s been a well-received idea.”

“Xeriscapes are really intended to reduce water use,” said U.S. Environmental Protection Agency environmental protection specialist Robert Goo. “They’re established using native plants or drought-resistant plants that don’t require a lot of maintenance.” In addition, the concept is not limited to arid climates but can be installed in humid or colder climates, as long as you find the right plants, he explained.
Creative landscaping could combine a Xeriscape garden with a rain garden, which is meant to control runoff. “You could design Xeriscaped rain gardens,” Goo said. “It really depends on what plants you select and what soil mixes [you use], based on geographic location.”
As the pressures of drought hit this summer, water utilities can use Xeriscape education as another tool to limit water use and improve water quality.

Jennifer Fulcher, WEF Highlights

Seven Principles of Xeriscape

  1. Planning and design. Create a plan taking into consideration the existing landscape, such as house, sidewalks, driveways, trees, slopes, and downspouts, and how you want to use the landscape, such as a decorative garden or utilitarian garden for vegetables. Decide on the types of plants to include.
  2. Soil improvements. If necessary, amend soils (especially clay- or sand-based soils) so they can absorb water and allow for deep roots by adding and mixing organic matter, such as compost or manure, into the soil.
  3. Efficient irrigation. Plan for irrigating while designing the landscape, grouping plants with similar water needs together. Water deeply and infrequently between 9 p.m. and 9 a.m. to develop deep roots. Install a rain shutoff device and adjust irrigation to meet seasonal needs and weather conditions.
  4. Zoning plants. Group plants with similar light and water requirements together in an area that uses water most efficiently, such as planting higher-water-use plants in low-lying drainage areas, near downspouts or in the shade of other plants.
  5. Mulching. Mulch helps keep plant roots cool, prevents soil from crusting, minimizes evaporation, and reduces weed growth. Apply organic mulches, such as bark chips or wood grindings, at least 100 mm (4 in.) deep and inorganic mulches, such as rocks and gravel, at least 50 mm (2 in.) deep.
  6. Turf Alternatives. Reduce the amount of turf grass in your landscape by replacing it with native or low-water-use plantings, patios, decks, or mulches to save water. 
  7. Appropriate Maintenance. Weeding, irrigation, pruning, fertilizing, and pest control are necessary activities of routine maintenance that keep the landscape attractive and water-thrifty. Maintenance time for a new garden is similar to traditional landscape, but it decreases over time.

These principles are provided by Denver Water. For more information, see www.denverwater.org/cons_xeriscape/xeriscape/xeriscapeprinciples.html.