14 January 2009
Virginia Cooperative Extension, Charlottesville/Albemarle County Office
460 Stagecoach Road, Charlottesville, Virginia 22902
phone: 434.872.4580 fax: 434.872.4578
Total rainfall in 2008 was slightly below what we might call a normal year and while it may not become a serious issue it is always good to be looking for ways to manage your landscape with less water. Minimizing the need for watering in your landscape requires careful observation, planning, and common sense.
The first step in any successful landscape is a good plan. Observe your site and take notes on the current use of different areas or their desired use. Indicate high-use areas, desirable views, environmental concerns (such as wind direction, slopes, dense shade), and traffic flow through the area. Sketch the property, including any permanent structures, trees, and shrubs that you plan to leave, grass areas, driveways, and sidewalks. Based on your notes, develop a plan that meets your needs for use, appearance, and budget.
Consider maintenance and water requirements in making your decisions. For example, maintaining a high-quality lawn area for entertaining will require frequent fertilizing and mowing, as well as some water use. A more maintenance-free choice for get-togethers is a deck or patio, but use wood or concrete in moderation. Leave plenty of vegetative surfaces for rain to reach the soil and soak in; otherwise, runoff and erosion problems are created.
Good soil is the basis for healthy plants and optimum use of water. The key to good soil is the addition of organic matter, such as compost. Ideally, you should incorporate approximately 2 to 3 inches of compost, shredded leaves, or other fine organic material to the soil annually.
In locations with established trees and shrubs, it is difficult to incorporate organic matter, but applying and maintaining a 2- to 3-inch layer of organic mulch (coarse leaves, shredded bark, pine needles, or wood chips) will gradually improve the soil as the humic acid formed by the decomposing material leaches into the ground.
Decide on the trees, shrubs, and ground covers for your water-wise landscape based on their natural ability to grow well in your area. Select plants that do well with little or no addition of water such as the tulip poplar. Look around and see what native plants are growing successfully nearby. Limit plants with high water demands to small areas that can be watered efficiently. Grouping plants by water requirements is one way to guard against over watering some plants and under watering others.
In general, ground covers require less water than turfgrass, so replacing some of your lawn with a ground cover will conserve water. If you have large deciduous trees in your yard and want to reduce work and water, allow leaves to accumulate as they would in nature. Plant a few understory shrubs (such as azaleas and rhododendrons) and a few understory trees (such as dogwood and redbud).
Organic mulches help retain moisture so there is less need to water. They also recycle plant materials that might otherwise end up in the landfill. In addition, mulches control annual weeds that compete with desired plants for water. Organic mulches improve soil structure as they decompose and they moderate the soil temperature, two factors that also help plants use water efficiently.
Mowing at the proper height (do not remove more than one third of the grass height at one time) allows the grass to develop deeper roots that are more efficient in using soil moisture, and reduces annual weeds. Fertilizing at the proper time encourages healthier turf that needs less watering.
Leaving trees and shrubs in their natural forms and planting them in their natural settings reduces environmental stress, allows them to better tolerate pests, and, therefore, lessens their need for water.
While soils vary greatly in their ability to hold water, your garden and lawn should receive enough water to wet the soil to the bottom of the root zone each time you water generally one inch per week. Check this by digging a hole 5 to 6 inches deep in the watered area the day after watering to see if it reached the bottom. This will allow you to adjust weekly watering to your soil needs.
Avoid watering by hand as it often wastes water as there is excess runoff, and water does not penetrate beyond the top one inch of soil. This irrigation practice harms plants by forcing root growth too close to the surface. If you must water by hand, place a five-gallon bucket with a few holes in the bottom next to the plant and fill it with water. When it is has drained, move it to the next plant and refill.
Properly used sprinkler systems can deliver a large quantity of water in a short time. They have the disadvantage, however, of excessive evaporation, both during watering and from the plant and soil surface. Early morning watering minimizes water loss. However, sprinkler systems that deliver the water from overhead are the most effective means of watering turfgrass. Be sure to position sprinklers to shower areas of vegetation, not driveways, streets, or patios.
Trickle or drip irrigation systems or soaker hoses are very efficient, slowly applying water to vegetable and ornamental gardens. Soil moisture can be maintained at a level most suitable to plant uptake. If properly installed and maintained little water is lost to evaporation or runoff and water use can be reduced by up to 50 percent. For many situations, the expense of installing a good-trickle irrigation system will be compensated by reduced water usage, less replacement of plant materials, and less work.
For more information about this and other landscape topics contact your local Virginia Cooperative Extension office. The local Virginia Cooperative Extension office numbers are Albemarle 872-4580, Fluvanna 591-1950, Greene 985-5236, Louisa 540-967-3422, and Nelson 263-4035.