Water Conservation in the Landscape - University of Idaho
CIS 990WATER CONSERVATIONIN THE LANDSCAPEJ. & ROBBINS, t FINNERTY, AND S. M. BELL - Increasingnumbersofgardeners want water per day comto use environmentally safe and energy- pared with the naconservingpractices to maintain healthy, tional average ofattractive landscapes. Their desire has 147. The populaproduced a type of landscaping that tion of Idaho is exreduces wateruse and maintenance, pro pected to grow by 30 percent in thetects water quality, and decreases pestcontrolneeds while itincreases thehealth 1990s, increasing the need for affordand beauty of the surroundings. Water able, consumableconservation in the landscape is an es water of high qualsential part of anenvironmentally sound ity. Conservation To reduce lawn expand patio space. Use brick or deck toapproach to gardening. can helpensure that allow air and water to reach the root zone of trees. By using the principles outhned in water will continue to be available. maintain attractive, healthy, and enthis publication, you can make more joyable yards and gardens. Water con Landscaping practices also affect theefficient use of water and still provide servation does not mean replacing all quality of our water. A recent Environbeauty and satisfaction in the landscape. lawns with pavement or having only mental Protection Agency study found As the demand for water increases, wa that nitrates - an ingredient in many cactus and rock gardens! Your exist ter-efficient landscaping will help con fertilizers and a common home lawn - ing landscapes already may incorpo serve this limited resource. were chemical pol and gardenherbicide rate one or two water conservation lutants of groundwater. ideas. With a little extraeffort, you canIdaho - implement an entire water-wise landfirst in wateruse Landscape water scape and significantly reduce water use. Water-wise gardening involves: Idaho is number one in per capitaconsumption of water in the United conservation * Design that stresses water conserStates. Idaho residents and nonagri You can take many steps toward vationcultural businesses use 311 gallons of becoming a careful water user and still * Soil analysis and preparationBEFORE AFTER - - * 4-. *T r-t Use mulch around trees and to gracefully extend the edges of shrub and tree zones Into former lawn space. * Unlversityot Idaho Cooperative Extension System 0 Agricultural Experiment Station
* Practical irrigated lawn areas* Appropriate plant selection* Effective and efficient water man agement* Use of mulches* Proper landscape maintenanceDesign that stresses waterconservation To create a water-efficient landscape, start by making a sketch ofexisting structures, shrub areas, trees,and lawns. Decide what changes you’dlike to make based on potential use ofthe area, sun exposure, maintenancelevel, water requirements, water availability, personal preference, and landscape budget. Group plants by water need, pre -ferred soil type, microclimate, andmaintenance requirements. For ex Before: The large lawn requires frequent watering, and many shrubs are poorlyample, you could group plants requir adapted to a dry climate.ing little water in an area that will not Spread organic matter such as shred cies and to develop grasses with lowerbe irrigated frequently or in an area ded bark or leaves, straw, peat moss, water requirements, such as turf-typewith sandy soil, which will not retain compost, sawdust, and grass clippings tall fescue.moisture. A microclimate is an area 2 to 3 inches deep on the surface of the Consider easeandefficiency ofwawith a specific climate due to its loca soil and thoroughly till it in. Bark, tering when deciding on lawn size,tion, such as the cool, shady, north side leaves, straw, and sawdust take extra shape, and location. Out-of-view propof a structure. Choose shade-adapted nitrogen to decompose. Add nitrogen erty perimeters such as road and driveplants for this microclimate. Sketch along with these materials, especially way edges can be planted with drought-out how the area will look when it is if you add them in spring. Nitrogen tolerant grasses and ground covers orfinished. You can complete the design will speed decomposition and prevent mulched with attractive rock or bark.gradually over several years. a possible nitrogen deficiency in the Irrigating long, narrow grass areas and plants you grow in the area. You could small, odd-shaped spaces is often anSoil analysis and pseparatlon also compost these materials before inefficient use of water. A mulch or Study the soil carefully, and match addingthem to the soil, decreasing the ground cover other than grass may beplants with their preferred soil type requirement for extra nitrogen. the best choice for these areas.and pH. Light. sandy soils fail to retain Preventing compaction and provid Patios and decks are useful insteadnutrients or water as well as clay or ing mechanical aeration increase the of lawn for outdoor living areas. Shrubloamy mixtures. Clay soils may have ability of the soil to absorb and store beds and ground covers instead of lawnpoor aeration and drain poorly. Some water. can create an attractive visual effect.plants grow in clay better than otherplants do. Practical irrigated lawn areas Appropriate plant selection Adding organic matter to the soil Lawn grasses require more frequent Select plants adapted to the growingconserves water and improves any soil watering and maintenance than most conditions. These plants should thriveas it increases overall plant health. other landscape plants. Carefully con in the soil, be adapted to the climateOrganic matter added to sandy soil sider the intended use of the yard be- cold hardy and able to withstand sumhelps to absorb water and nutrients fore deciding how much lawn to in mer temperatures, and have a goodand to hold them in the root zone. stall. level of resistance to the diseases andOrganic matteralso loosens heavy soils Choose the grass species carefully. insects common to the area. Manyand improves drainage. aeration, and Much research is being done to deter native species are well adapted andworkability. mine water requirements of grass spe need little irrigation.
pings or of inorganic materials such as rock and permeable or impermeable plastic sheeting. Impermeable plastic mulches can decrease soil aeration and encourage shallow rooting, while rock can compact the soil and heat up an area. Fine mulches, such as sawdust, may also encourage shallow rooting. All mulches conserve water by re ducing soil moisture evaporation and weed growth. Organic mulches pre vent soil compaction, add organic matter, and moderate soil tempera tures. Rock and plastic sheeting do not. Inorganic and organic materials are often combined. For example, per meable plastic sheeting can be cov ered with a bark layer. Ptcper landscape maintenance To reduce water use in the landAfter: Lawn has been replaced by payers, mulched shrub areas, and plants with low scape, check the sprinkler system peri water needs, making the area water conserving as well as low maintenance. odically especially if it is an under Many well-adapted exotic plants however, they adapt to less frequent ground system, time insect and disalso are available and require low wa watering. Most well-established trees ease control correctly to reduce plantter input. Limited use of annuals, which and shrubs require several deep stress, and eliminate weeds.generally require heavy watering, can waterings in the root zone during the Proper maintenance of the lawn isprovide summer color. growing season moist to a depth of 12 critical. Mow the grass at the recom to 18 inches. Applying the properEffective and efficient water amount of watercan take several hours, especially for large trees. The actual "Xeriscape," a term patentedmans time depends on soil characteristics by the National XeriscapeCoun Apply water so that it is available to and the irrigation system. Soakerhoses cil, emphasizes the use ofthe plants. Applied too rapidly, water and drip irrigation work well for this drought-tolerant xeric plantis lost to runoff. Applied on exposed, type of watering. species combined with creativeunmulched soil, water evaporates. Drip irrigation or pop-up sprinklers landscaping practices to conserveOther causes of wasted water are that apply water directly to where it is water. "Mesiscape" originated inevaporation into the air from sprin needed are extremely water efficient. Massachusetts where the climateklers and runoff from nonabsorbing Use them throughout the landscape is moderately moist mesic, butareas, such as sidewalks and streets. when possible. water quality and quantity are The greatest waste of water is ap Run sprinklers between late evening still critical factors. Mesiscapeplying too much, too often. Not only and midmorning to reduce waste emphasizes using landscape techdoes this practice waste water, but it through evaporation. Mechanical or niques that enable moderatelyleaches nutrients deep into the soil and electronic timers on hoses, drip lines, drought-tolerant plants to growaway from plant roots, increasing the and sprinklers turn off the water auto in dry conditions. Xeriscape andchances of polluting groundwater. matically after the desired amount has mesiscape apply to Idaho withWater lawns infrequently but deeply been applied. its dry environments inthe southmoist to a depth of 12 inches. Deep, ern and central regions and seainfrequent watering promotes a deeply Use of mulches sonally moist northern environrooted lawn that is more water effi Mulch is a layerof nonliving mate ments. Xeriscape and mesiscapecient and more drought tolerant. rial that ôovers the soil surface. This include many techniques for All trees and shrubs require fre layer may be composed of organic merly associated with low-mainquent watering for a year or two after materials such as bark, compost, wood tenance landscaping.planting. After they are established, chips, straw, sawdust, and grass clip-
mendedheightforthe species. Heights less water to become established dur tions. Contact Bob Mahler, Departof 2 to 3 inches allow the grass to ing this cooler period and can develop ment of Plant, Soil and Entomodevelop a deep, water-efficient root deeper, water-absorbing roots before logical Sciences, College of Agrisystem. This taller grass forms a living the onset of warm summer weather. culture, University of Idaho, Mosmulch, shading the ground to reduce cow, ID 83844-2339.soil moisture evaporation and retard Further leading Books:ing weed growth. As the grass grows University of Idaho Cooperative Ellefson, C., T. Stephens, and D.taller and matures, it requires less wa Extension System publications: Welch. 1992. Xeriscape gardening:ter and less frequent mowing. Leaving To order, contact the University of water conservation for the Amerigrass clippings as a mulch improves Idaho Cooperative Extension System can landscape. New York:soil structure, soil fertility, and water office in your county or write or call Macmillan Publishing Co.retention. Clippings do not cause - Agricultural Communications, Idaho Knopf, J. 1991. The Xeriscape flowerthatch in lawns. Street, University of Idaho, Moscow, gardener: A waterwise guide for the Fertilize only as often as necessary Idaho 83844-2240 208-885-7982. Rocky Mountain region. Boulder,to maintain a healthy, green landscape. * CIS 168, Landscape Your Home Colorado: Johnson Publishing Co.Avoid lush, rampant growth. Timing Grounds, 350 The authors Jo Ann Robbins, Ex -of fertilizer applications will depend C’S 731, Thatch in Lawns, 25o tensiOn agricultural agent, Blame County,on the plants in the landscape and the Hailey; Terry Finnerty, Extension associ CIS 837, Mulchesfor the Home Land ate, Department of Plant, Soil, and Entoexisting fertility ofthe soil. Have a soil mological Sciences, Sandpoint Research scape and Garden, 35otest run every 3 to 5 years to determine and Extension Center, and Susan M. Bell,the need for nutrients. Moderate use of CIS 858, Using Bark and Sawdustfor Extension agricultural agent, Ada County,fertilizer can save time, labor, money, Mulches, Soil Amendments Boise. Artwork on page 1 reproduced byand water. It will also reduce the po and Potting Mixes, 350 courtesy of The National Arbor Day Foun CIS 887, Idaho’s WaterResource, free dation, Nebraska City, NE. Illustrationstential for groundwatercontamination. on pages 2 and 3 reproduced by courtesy Seed new lawns and plant new plants WQ- 1, Activities in Water Quality, of Sunset Publishing Corporation, Menloin the early spring. New plants require free Unavailable from Ag Publica Park, CA. Issued in furtherance of cooperative extension work in agriculture and home economics, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, LeRoy D. Luft, Director of Cooperative Extension System, University of Idaho, Moscow, Idaho 83844. We offer educational programs, activities, and materials without regard to race, color, religion, national origin, sex, age, or disability, in accordance with state and federal laws.2.000 4.93 50 cents