The need for landscaping to conserve water received new attention following the drought of 1977 throughout the western states and the recognition that nearly 50 percent of the water used by the average household is for maintaining landscaping grass and plantings.
Soil preparation is key to water preservation. If the soil is very sandy, water and valuable nutrients will be lost due to leaching below the root zone. If your soil is heavy clay, common in this area, you will lose water by runoff. A good soil is one that supports healthy plant life and conserves moisture and has a balance of rather coarse soil clusters. The “ideal” soil has as much as 50 percent by volume pore space, with the soil itself consisting of a good balance of sand, silt and clay.
A major problem with heavy soils is that clay tends to dominate the soil complex. Clay is composed of microscopic crystals arranged in flat plates. When a soil has a high number of these crystals, they act much like a glue, cementing the particles of sand and silt together and resulting in a compact, almost airless soil. Such soils usually repel surface water, resulting in runoff. The small amount of water that does get into these soils is held so tightly by the clay itself that plants cannot use it. Sandy soils have very large pore spaces. Because the particles are large, there is little surface area to hold the water, so sandy soils tend to lose water rapidly.
Colorado State education’s extension programs says, “Xeriscaping (zer-i-skaping) is a word originally coined by a special task force of the Denver Water Department, Associated Landscape Contractors of Colorado and Colorado State University to describe “landscaping with water conservation as a major objective.” The derivation of the word is from the Greek “xeros,” meaning dry, and landscaping — thus, xeriscaping,” a perfect concept for gardening in Colorado.
Properly selected and applied mulches in flower and shrub beds reduce water use by decreasing soil temperatures and the amount of soil exposed to wind. Mulches allow for better use of water, discourage weeds, and can improve soil conditions. Proper irrigation practices can lead to a 30 to 80 percent water savings around the home grounds. If a sprinkler system is already installed, check it for overall even coverage. You don’t want watering to cause pools or puddling in some areas and not reach others.
It is suggested that “irrigating turf areas differently than shrub borders and flower beds,” will get better results. North and east exposures need less frequent watering than south and west exposures. Apply water to slopes more slowly than to flat surfaces. Examine these closely and correct inefficiencies in irrigation system design. If you do not have a sprinkler system and are just beginning to install a landscape, you can avoid the pitfalls of poorly designed and installed systems. Have a professional irrigation company do the job correctly.
Whether you want to redesign an old landscape or start fresh with a new one, a plan is a must. The plan does not have to be elaborate but should take into consideration the exposures on the site. As a rule, south and west exposures result in the greatest water losses, especially areas near buildings or paved surfaces. You can save water in these locations simply by changing to plants adapted to reduced water use. However, do not be too quick to rip out the sod and substitute plastic and gravel. Extensive use of rock on south and west exposures can raise temperatures near the house and result in wasteful water runoff.
Slope or grade is another consideration. Steep slopes, especially those on south and west exposures, waste water through runoff and rapid water evaporation. A drought-resistant ground cover can slow water loss and shade the soil. Landscape designers will employ all the principles of Xeriscaping when designing your landscaping project – elements like limiting sod area that require lots of watering, drought resistant sod and plant materials, moisture sensing watering systems, rock and mulch areas that blend into more lush planting areas for not only better water conservation but a tremendously beautiful landscape year after year.
Whether you are a water conservationist at heart or just trying to maintain a lower water utility bill, xeriscaping can offer great results. Consider developing a customized plan with your local landscape designer or architect to maximize your investment and increase your satisfaction for a sustainable garden with lasting memories.