Is one of your New Year’s resolutions to save more money? One way you can do this is by conserving water in your landscape, and now is the time to make plans. Some people try to conserve water by removing their lawn, or even all plants from their yard. But this usually backfires. Planted areas serve an important function. Trees in your landscape provide needed shade in the heat of summer, and strategically placed evergreen trees block cold winds in the winter, so they help lower heating and cooling costs. Planted areas also intercept sunlight and reduce the drying effects of reflected heat; they cool your yard and our urban areas by moving water from the soil to the air through their leaves, providing evaporative cooling and increasing humidity.
An alternative to paving over your yard is to redesign it to be more efficient. This is easier than it sounds. Start by evaluating your current situation. Get out in your yard and observe. Where is water currently being wasted? Are their areas of lawn that only see foot traffic when you mow? Where are the sunny and shady areas? Do you have areas where some plants are overwatered and others not getting enough?
One of the most important principles of water-efficient landscaping is grouping plants by their water needs. This is called hydrozoning, and it means you’ll have to do a bit of research to find out how much water your plants require. Plant tags from your retailer will often provide this information, but when in doubt, check with your local University of Nevada Cooperative Extension office. Lawns require the most frequent watering of any plants in your yard, so at the very least you should water your lawn separately from the rest of your plants. This means setting up your lawn on its own irrigation valve. Because most lawn grasses are shallow-rooted (6 to 8 inches), they require deep watering two to three times per week. Other plants such as trees and shrubs have deeper roots (18 to 24 inches), so they require longer watering times but less frequently (once every week or two). Of course, all plants will require regular water during their first season after planting, until a sufficient root system is established.
Minimize lawn to correspond to areas of high use, such as child or pet play areas and entertainment areas, and to areas that provide defensible space for fire prevention. Grass should be mowed frequently to a height of 3 inches to encourage deeper rooting. Deep rooting allows your grass to weather hot dry conditions more effectively.
Plants in sunny areas of your yard need to be watered more frequently than plants in shady areas. Put water-thirsty plants in areas that get at least partial shade during the day to minimize their stress. Sunny areas should be reserved for drought-adapted plants, or should be hydrozoned to receive more frequent watering.
Use mulch around plants to help prevent evaporation of water from the root zone. Trees, especially, benefit from mulch placed around their base. Mulch should be applied to a depth of 2 to 4 inches in a circle as wide as the tree canopy (the area that provides shade when the sun is directly overhead), and should be kept about 2 inches away from the trunk to prevent rotting or rodent damage. Many types of mulch are available. Good mulches are organic in nature, so as they break down, they add organic matter and nutrients to the soil. Organic mulches include bark chips, shredded bark, and shredded or chopped discarded plant parts that are free of pesticides or weed seeds. Inorganic mulches such as rock, crushed stone and decomposed granite are also popular, but keep in mind that they will reflect more light and heat than organic mulches. Their use should be limited to plants adapted to hot, dry conditions.
Finally, take a good hard look at your irrigation system. As the weather begins to warm in spring, test it to make sure there are no leaks or breaks in the lines, and that all parts are working properly. Consider converting to drip irrigation in non-turf areas for greatest efficiency. Pop-up sprinklers are only about 65 percent efficient, whereas drip systems are up to 90 percent efficient. Lawn areas should get head-to-head coverage from sprinkler heads. You can test this by placing straight-sided soup cans equally spaced around your yard and turning your irrigation system on for about ten minutes. Measure the depth of water in each can to make sure they are about equal. Adjust your sprinkler heads as needed to provide equal water application across your lawn. Don’t hesitate to get professional help in adjusting your irrigation system for efficiency. For more information on water-efficient landscaping, contact University of Nevada Cooperative Extension at 775-784-4848.
Dr. Heidi Kratsch is the University of Nevada Cooperative Extension horticulture specialist. She can be reached at KratschH@unce.unr.edu.
7 principles of water-efficient landscaping:
- Group plants according to their water needs.
- Analyze and improve your soil.
- Select native and climate-adapted plants.
- Limit turfgrass to areas needed for practical use.
- Mulch around plants.
- Use and schedule irrigation efficiently.
- Provide regular maintenance.