By: Douglas F. Welsh, Extension Horticulturist , William C. Welch, Extension Landscape Horticulturist, and The Texas A&M University System
Water has become a critical issue for the future prosperity of Texas. Booming populations have increased the demand on the state’s already limited supply of high-quality water. In addition, seasonal fluctuations in rainfall and periodic droughts create a feast-to-famine cycle in Texas.
In urban areas, about 25 percent of the water supply is used to water landscapes and gardens. In the summer, as much as 60 percent of the water the average household uses may be for landscape maintenance Many traditional landscapes require large amounts of water, and much of this water is applied inefficiently.
To reduce the excessive use of water for maintaining landscapes, the Texas Agricultural Extension Service encourages Texans to adopt Xeriscape landscaping. This concept conserves water and protects the environment. Xeriscape landscapes need not be cactus and rock gardens. They can be cool, green landscapes full of beautiful plants maintained with water-efficient practices.
The seven water-saving principles of Xeriscape landscaping are not new; they have been practiced in the landscape industry for decades. Combining all seven into a comprehensive program of landscape water conservation is what makes Xeriscape landscaping unique. The principles are:
- Planning and design
- Soil analysis and preparation
- Practical turf areas
- Appropriate plant selection
- Efficient irrigation
- Use of mulches
- Appropriate maintenance
By incorporating these seven principles, you can help preserve our most precious natural resource—water.
Start With a Plan
Creating a water-efficient landscape begins with a well-thought-out landscape design. Sketch your yard, showing the locations of buildings, trees, shrubs, gardens and grass areas. Then consider how you use the various areas of your yard, how you want your yard to look, the amount of maintenance you plan to give it, and the budget you can afford. Also pinpoint the areas of your landscape that require the most water. The purpose of planning is to design a landscape that will have the appearance and function you desire while conserving water. Local landscape architects, designers, nurserymen and county Extension agents can help in this decision making. You can implement your landscape design gradually over several years.
Analyze and Prepare the Soil
Have your soil tested. (Your county Extension agent can tell you how.) The test results will tell you what kinds and amounts of fertilizer your soil needs, and whether you should add organic matter. Most soils benefit greatly from organic matter. Adding organic matter to the soil of shrub and flower bed areas makes plants healthier. Organic matter also helps the soil absorb and store water. As a rule-of-thumb, till in 4 to 6 inches of organic material such as shredded pine bark, compost or leaves. It is not necessary to incorporate organic matter for trees, and for large turfgrass areas it is not economically feasible.
Be Practical with Turf Areas
When designing the landscape, keep in mind that turfgrasses need more water and maintenance than most other plants. To conserve water, reduce the size of the lawn by including patios, decks, shrub beds and groundcovers in the landscape design.
Also consider the ease of watering turf areas. Areas that are long and narrow, small, or oddly shaped are difficult to water efficiently. Confine grass to blocky, squarish areas that are easier to maintain.
Select Appropriate Plants
Select trees, shrubs and groundcovers that are adapted to your region’s soil and climate. Texas is blessed with an abundance of beautiful native plants from which to choose. Most require less water and fertilizer and have fewer pest problems than non adapted exotic plants that have been introduced into Texas landscapes.
Native Texas plants are becoming more available at retail nurseries and garden centers. Combining Texas natives with well adapted exotic plants is one key to a beautiful, interesting landscape that conserves water.
When it comes to selecting a turfgrass, remember that the different varieties have very different water requirements. One of the best ways to conserve water is to select a grass that is adapted to your area of the state and that has a low demand for water.
Refer to the tables in this publication for landscape plants adapted to and recommended for your area. Your county Extension agent or local nurseryman also can make suggestions.
Tremendous amounts of water are applied to lawns and gardens, but much of it is never absorbed by the plants and put to use. Some water runs off because it is applied too rapidly, and some water evaporates from exposed, unmulched soil; but, the greatest waste of water is applying too much too often.
When too much water is applied to the landscape it can leach nutrients deep into the soil away from plant roots, and possibly pollute groundwater. Runoff also can cause pollution by carrying fertilizers and pesticides into streams and lakes. These problems can be eliminated with proper watering techniques.
Most lawns receive twice as much water as they need. The key to watering lawns is to apply the water only when the grass needs it, but water thoroughly. This creates a deep, well-rooted lawn that efficiently uses water stored in the soil.
To know when to water the lawn, simply observe the grass. Wilting and discoloration are signs of water stress. At the first sign of wilting, you have 24 to 48 hours to water before serious injury occurs. Apply 1 inch of water to the lawn as rapidly as possible without runoff.
Trees and Shrubs
Newly planted trees and shrubs should be watered frequently until they are well rooted, which may take two growing seasons. Once established, plants should be watered less frequently so they will develop deep roots and be better able to withstand drought.
In the absence of rain, most trees and shrubs benefit from a once-a-month, thorough watering during the growing season. Normal lawn watering is not a substitute for thorough tree and shrub watering. The feeding root system of a tree or shrub is located within the top 12 inches of the soil and at the “dripline” of the plant. The dripline is the area directly below the outermost reaches of the branches. Apply water and fertilizer from just inside to a little beyond the dripline, not at the trunk. Simply lay a slowly running hose on the ground and move it around the dripline as each area becomes saturated to a depth of 8 to 10 inches. For large trees, this watering technique may take several hours.
Sprinkler irrigation. Most people water with sprinklers—either hose-end sprinklers or permanent, underground systems. A permanent sprinkler system can be more water-efficient than a hose-end sprinkler, but both systems require little maintenance and apply large volumes of water in a short time. If you have a permanent sprinkler system, make sure the sprinkler heads are positioned properly to avoid watering sidewalks and driveways. Also adjust sprinkler heads so that they spray large droplets of water instead of a fog or fine mist, which evaporates quickly and may drift away with the wind. With either hose-end sprinklers or permanent systems, water between late evening and mid-morning so that water won’t evaporate quickly and be wasted.
Drip irrigation. Drip irrigation is more efficient and more beneficial to plants than sprinkler irrigation. In areas of the state where water quality is poor (i.e., high salt content), drip irrigation is also safer for landscapes. Drip irrigation slowly applies water to soil. The water flows under low pressure through emitters, bubblers, or spray heads placed at each plant. There is little chance that water applied by drip irrigation will be wasted by evaporation or runoff. If you aren’t familiar with drip irrigation, seek advice from professionals and experiment with it in small sections of the landscape. This will acquaint you with the benefits of drip irrigation.
Conserve Moisture with Mulches
Mulch is a layer of nonliving material covering the soil surface around plants. Mulches can be organic materials such as pine bark, compost and woodchips; or inorganic materials such as lava rock, limestone or permeable plastic (not sheet plastic).
Use a mulch wherever possible. A good mulch conserves water by significantly reducing moisture evaporation from the soil. Mulch also reduces weeds, prevents soil compaction, and keeps soil temperatures more moderate.
Use Good Maintenance Practices
Mowing grass at the proper height conserves water because it encourages root systems to grow deeper and become more water-efficient. Mow St. Augustinegrass and buffalograss at 3 inches, Bermudagrass at 1 inch, centipedegrass and Zoysiagrass at 2 inches.
Fertilizing the lawn at the proper time and using the proper amount can save time, effort and money by reducing mowing and watering. Fertilizers also can be a major source of pollution of streams and groundwater if too much is applied. Fertilize the lawn once in the spring and again in the fall. Use a slow-release form of nitrogen in the spring application and a quick-release form in the fall. Apply only 1 pound of actual nitrogen fertilizer per 1,000 square feet of lawn at one time. With this schedule, no other fertilizer is needed to maintain most shrubs and trees in the lawn area.
Check your irrigation system periodically and maintain it so that it will operate efficiently. Properly time any insect and disease control measures, and eliminate weeds (they compete with other plants for water).
A well-designed landscape that uses Xeriscape principles can reduce maintenance by as much as 50 percent through reduced mowing, once-a-year mulching, the elimination of unadapted plants that require lots of water, and efficient irrigation.
Commit to Water Conservation
Water must be a vital concern for everyone in Texas because it is a limited and fragile resource. Many people believe that watering landscapes is a nonessential luxury. In times of severe drought, rationing may limit the amount of water we can use for our lawns and gardens. Therefore, Texans have a special responsibility to conserve water and protect its quality. Xeriscaping conserves water in the landscape without sacrificing beauty and plant diversity. By following these guidelines, you can proudly create your own Xeriscape landscape.
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