In the Garden:
Southwestern Deserts
May, 2012
Regional Report

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Decide how much lawn you really need!

Xeriscape Part II: Turf

Xeriscape design includes a set of seven principles to guide you in the creation and long-term maintenance of a colorful, earth-friendly landscape that suits your unique needs. Previous reports covered design and site assessment. Next up: turf.

Xeriscape principles allow for the possibility of small areas of grass in a landscape -- if wisely designed, properly installed, and well maintained. These are important ifs.

Some xeriscape guides cover the topic of lawns later in the discussion. I'm covering it early because whether or not you install grass directly influences all of the other steps, including design, plant selection, irrigation system, maintenance, and soil amendments. It also influences your budget. You may decide you don't need grass at all, which will save expense, time, labor, money, and natural resources over the long haul. Here I'll cover some of the basic pros and cons of grass, followed by design considerations, and will cover installation and maintenance in the future.

Grass: Pros and Cons
Grass, considered just as plant material, does provide benefits. A lawn acts as an evaporative cooler, reducing temperatures around the home. Lawns trap and hold rainwater on the property, prevent soil erosion, break down and absorb pollutants, and produce oxygen. Grass is a good option for play areas for kids. Many people appreciate the green appearance of a lawn.

Unfortunately, expansive lawns come at considerable environmental cost. Grass requires enormous quantities of water and fertilizer to survive in the desert. Chemical (synthetic) fertilizers, herbicides, and insecticides applied to lawns create "non-point source pollution" (pollution derived from many potential sources, rather than one fixed site, such as a factory). Lawn fertilizers contain nitrogen, to green up the grass. Nitrogen, in the form of nitrate, is completely soluble and leaches through the soil into groundwater supplies or can be carried along with soil particles or other particulates into surface water such as streams and lakes. Elevated nitrate levels in drinking water reduce the blood's ability to transport oxygen, which is bad for everyone but particularly problematic in infants.

Phosphorus, also found in lawn fertilizers, may also end up in lakes and rivers and contributes to algae and weed growth that can alter the natural plant and fish populations. The manufacture and transport of these chemicals also consumes resources and produces carbon emissions. Gas-powered mowers and blowers use fossil fuels, produce particulates, and contribute to poor air quality that is serious for children with asthma or people with respiratory problems. Not to mention the annoying noise pollution of whining blowers!

Design Considerations
Get out your design list and site assessment (discussed in earlier reports) and contemplate whether you need a lawn. If you want a safe play area for kids or pets, that's understandable, and grass does provide the most forgiving surface for running, jumping, and tumbling around. However, it's unlikely that an entire property needs to be covered in grass. Determine how much space is needed for your particular use.

Also, be sure you have the appropriate conditions for grass to thrive, including at least eight hours of full sun. There is no turf grass variety that grows well in shade or beneath tree canopies in the desert! Grass grown in the shade will be patchy and unattractive. Also, take into consideration buildings that may cast shade on an area, depending on the angle of the sun during each season. Factor in young trees that will have spreading canopies in a few years. Maybe it works to have a patch of grass for a few years while kids are young, and by the time the tree matures and shades the grass, you'll be ready to replace the lawn.

If you determine that what you really want is "a green look", consider groundcovers or a blend of groundcovers, succulents, and low-growing perennials that offer greenery with lower water needs, no need for soil amendments, minimal maintenance, and probably no fertilizer.

Front Yard Grass
Okay, this is my pet peeve. The vast majority of front yard grass that I see in the low desert is wasted and/or wasteful. Most people don't allow their kids or pets to play out front near the street and families seldom congregate for recreation on the front yard. I do see many "dog visits" by neighbors taking place on front lawns, but ask yourself if you want to maintain a lawn for others' dogs to do their duty?!

In the 1980s and 90s, there was an unfortunate trend among landscape companies to install oddly shaped patches of grass in the front yard -- kidney beans and scalloped edged ovals, perhaps surrounded by short sections of upended railroad ties and the like. They were a maintenance headache. It's impossible to effectively and efficiently set up sprinkler heads to irrigate such shapes. Water sprays over the edges onto sidewalks and driveways, running into the street, creating cracks and erosion over time. Mowing, edging, and other maintenance chores of odd shapes are more time consuming than squares or rectangles.

I think it's interesting that in a neighborhood near my house with 20 or so homes, all starting with kidney bean and other little splats of front yard grass in the 80s (installed by the developer), only one remains. Over the years, homeowners wised up to the uselessness and hassle and expense of maintaining these patches that didn't look very healthy anyway because of the difficulty in watering effectively and converted to well-adapted desert plants.

Budget Considerations
If your landscape budget is limited, realize that before planting a lawn, the soil must be carefully prepared and amended and an automatic sprinkler system installed. Don't skimp on this. Proper soil prep is key to growing a healthy lawn for years to come. Desert-adapted plants do not require soil amendments. Most people install a drip irrigation system to water landscape plants, although again, if money is tight, you can get away with hand-watering desert plants, assuming you are diligent about monitoring their needs. Depending on the plant, they establish in about three years, so after that, you have more leeway between watering.

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