The concept of xeriscaping sometimes receives a black eye from folks who mistakenly label hot expanses of decomposed granite dotted with cacti and cow skulls as xeriscape. In fact, implementing xeriscape’s true principles produces a colorful shady refuge that offers year-round interest and recreational opportunities. It may surprise you, but xeriscape principles even allow for grass.
The key is to install a lawn that is practical in size and optimally maintained to reduce environmental impact. Although not part of xeriscaping, synthetic grass often is touted as a low-maintenance, water-conserving alternative to the real thing. The following information can be used to help sort out some of their differences.
NATURAL GRASSImproves air quality—Aboveground grass blades and extensive root systems capture pollutants such as dust, ozone and sulfur dioxide, breaking them into elements that can be used by grass. Like other live plants, grass lawns absorb carbon dioxide and release oxygen, a process essential for life on Earth.
Cools surroundings—Grass acts as an evaporative cooler, lowering surrounding air temperatures. Salt River Project (SRP) tested surface temperatures of natural grass, synthetic grass, xeriscape and asphalt during a July day’s peak heat (110 degrees). Natural grass was the coolest at 100 degrees.
Requires maintenance—Lawns need regular watering, mowing, fertilizing and weeding, as well as periodic aerating, dethatching, and, in the case of winter ryegrass, optional overseeding. Related environmental concerns include excess water use; runoff from nitrogen fertilizer or pesticides that pollute groundwater and surface water; and energy consumption and air pollution generated by gas-powered mowers and blowers.
SYNTHETIC GRASSThe exposed top layer of synthetic turf is a carpet of flexible plastic and/or nylon “blades.” A coarse infill is typically added to help hold the carpet in place and keep blades upright. Infill is commonly made of recycled tires, called “crumb rubber.”
Requires less maintenance than natural grass—Hosing is needed to remove dust and debris and cool its surface. Raking refreshes its appearance. Maintenance frequency depends on the surroundings and one’s tolerance for a pristine surface. Also, weeds will appear in synthetic grass over time.
Hot surface—In SRP’s temperature test, synthetic turf was the hottest surface at an unbearable 165 degrees. Synthetic turf cooled off when shaded and did not radiate heat like asphalt does.
Recycles waste products—Because synthetic grass includes recycled materials—such as rubber tires—the content and concentration of COPCs (chemicals of potential concern) may vary among products. Questions were raised in 2008, when lead was found in some artificial turf fibers. The U.S. Consumer Product Safety Commission asked the synthetic turf industry to remove all added lead and develop a testing standard to ensure that it is not added. However, lead still may be a byproduct as the materials de-grade. Research on the long-term deterioration of synthetic turf and crumb rubber, including effects on users (adults, children, pets) and the environment, is in its infancy.
MORE CONSIDERATIONSAsk yourself the following: In what type of surroundings do you want to spend your time? Who is using the grass and for what purpose? Are kids and pets involved? What time of day will you be using the area? What is the sun exposure year-round? What other plants exist or are planned? Take into account that lack of irrigation and intense soil heat beneath synthetic grass in summer sun may be detrimental to the spreading root systems of nearby trees.
If you aren’t sure that grass—real or synthetic—is what you want, consider an alternative green option. “For most folks, the square footage of real or synthetic turf they are considering can easily support a tree instead,” observes Jo Miller, from the city of Glendale’s Environmental Resources Water Conservation Office. “Trees offer numerous benefits, such as reducing energy bills by shading the house and creating a cooler space to enjoy outdoor living and play areas,” says Miller. Visit the free Glendale Xeriscape Botanical Garden for tree ideas.