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Landscape Design for Water Conservation - University of FloridaDocument Transcript
ENH72Landscape Design for Water Conservation1Knox, Gary W.2 Water conservation is becoming an important evolved to reduce water and maintenancepart of Floridas overall water management program. requirements while still providingSaltwater intrusion and pollutants threaten Floridas aesthetically-pleasing landscapes. Collectively,limited water resources, and increasing urbanization landscaping concepts that reduce water requirementsand periodic drought are placing greater demands on can be called xeriscape™ landscaping orwater supplies. For these reasons, nursery growers, xeriscaping™. Xeriscape™ is a new word coinedlandscapers, and homeowners should be conscious of from the Greek xeros, meaning dry and the wordwater use and should strive to minimize waste and landscape. Xeriscaping™ was originally conceived inconsumption of water. One of the best means of the southwestern U.S., although it was inspired byconserving water is to design or modify the landscape the gardening traditions of Spain, north Africa, andto reduce its water requirements. the Mid-East and by the natural landscapes of the Southwest. LANDSCAPE STYLES One component of water-conserving landscapes The ``traditional or ``conventional landscape is the concept of natural or ecological landscaping.is characterized by large areas of turf accented by Natural landscaping involves plant selection that iswell-manicured trees and shrubs. This traditional based on climate and environment of the area as welllandscape is typical of the cool, temperate regions of as site characteristics of exposure, light intensity, soilthe northeastern U.S. and was brought to Florida as pH, soil aeration, soil mineral analysis, site drainage,people moved here from the North. Unfortunately, and irrigation water quality. Proper plant selectionthis traditional type of landscape is not well-adapted based on site characteristics should enhance theto Floridas sandy, porous soils; hot, sub-tropical plants likelihood of becoming established in the siteclimate; and well-defined wet and dry seasons. As a and reduce potential incidences of low vigor,result, traditional landscapes in Florida require large excessive maintenance, disease, or death.amounts of water and maintenance. Native species are often preferred for natural In response to drought and limited water landscapes but plant selection should take intoresources a number of new landscaping ideas have consideration the microclimate and topography of the1. This document is ENH72, one of a series of the Environmental Horticulture Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date June 1990. Revised March 1991. Reviewed October 2003. Visit the EDIS Web Site at http://edis.ifas.ufl.edu.2.The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information andother services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex,sexual orientation, marital status, national origin, political opinions or affiliations. U.S. Department of Agriculture, Cooperative Extension Service,University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. LarryArrington, Dean
Landscape Design for Water Conservation 2site. In some cases, native plants will not be the most grouping plants in the landscape according to theirappropriate choice because mans development of a water requirements. By grouping plants with similarsite can greatly alter the microclimate and water needs, the irrigation system can be zoned sotopography. Development can result in man-made that each group receives only the amount of waterdeserts (i.e. parking lots), swamps (i.e. retention required to maintain the plants. This technique hasponds, waterways), and artificially-shaded areas. the additional advantage that plants on the sameThus, effective xeriscaping™ should match plants irrigation set will not be under or over watered at thewith the microclimatic features of the developed expense of other plants.landscape site. For example, plants adapted to wetsoils should be used in low spots, waterways, An additional way to reduce maintenance andretention ponds, spillways, and areas with poor water use is to increase the use of mulches. A three-drainage; drought tolerant plants should be used in to four-inch layer of mulch should be used in plantingdry spots, windy areas, exposed areas, plantings on beds to reduce evaporation from the soil surface,berms, and plantings in areas against unshaded south moderate soil temperatures, and suppress weeds.or west walls of buildings. Mulches can sometimes replace turf or groundcovers in areas where they require extensive watering or do Since natural landscaping is a rather abrupt not cover an area completely. In these situations,change in U.S. landscaping philosophy, it may be mulches provide the additional benefits of requiringdifficult for the public to accept natural landscaping less maintenance and not consuming water.because of their preconceptions of what a landscapeshould look like. One way to satisfy the desire for Two more aspects of design that reducetraditional landscapes and the need for low water irrigation needs are the use of drought tolerant plantsrequiring, low maintenance landscapes is to use the and windbreaks. Drought tolerant plants inherently``oasis approach to landscape design. Oasis require less water because they are adapted to ariddesigning involves placing high water requiring, high areas or to regions with frequent drought or with soilsmaintenance, and showy plants in the areas with the of low water holding capacity.most visual impact, i.e., entranceways, primary If using turf in the landscape, consider using oneviews, patios, courtyards, etc. The oasis area has the of the more drought tolerant species. Grasses withmost elaborate irrigation system and requires the excellent drought tolerance include: bahiagrass,most water and maintenance. Bermudagrass, and zoysiagrass. A good drought Other areas with less traffic or less visibility use tolerant plant is centipedegrass while St.lower water requiring, low maintenance plantsfor Augustinegrass has a fair rating. Carpetgrass has aexample, sides of buildings, service areas, and more very poor drought tolerance rating (Augustine andremote areas of the landscape. A transition zone Peacock, 1985). Another alternative with bahiagrassexists between these two areas which uses plants that is to allow turf to go dormant during dry periods;require less water than the oasis planting but more bahiagrass will turn green again when rains resume.than the natural area. The oasis concept improves Windbreaks can be formed by walls, fences,water management practices because it concentrates shrub beds, or hedges. Windbreaks reduce windwater resources in plantings close to main use areas. velocity and can greatly reduce water loss that occursAn additional benefit is that it reduces irrigation costs by evaporation during irrigation and byby concentrating irrigation equipment and by placing evapo-transpiration from plants. Properlythe systems in areas that are usually closer to water constructed, windbreaks can reduce wind velocity bylines. 75% to 85% and should be strongly considered for OTHER ASPECTS OF DESIGN areas that experience steady winds or frequent gusty winds. Effectiveness of windbreaks is determined by Aside from these landscaping philosophies, height, density, and shape, with height having thelandscape design for water conservation can include greatest influence. The area protected by the windbreak extends downwind the distance of five
Landscape Design for Water Conservation 3times the height of the windbreak. For optimum Donselman, H. and T. Broschat. 1987.effectiveness, the windbreak should be continuous Xeriscape™ Plant Guide. Water Use Planning and(unbroken by gaps) ``stair-step in shape, at least Management Division, South Florida Waterhead-high, moderately dense (not impenetrable), and Management District, West Palm Beach, Florida. 32evergreen. pp. SUMMARY Flemer, W., III. 1987. Biologically Sensitive landscapes save plants and money. American Water requirements of landscapes can be Nurseryman 165(11): 67-70, 74, 76, 78.reduced by using the design principles of naturallandscaping or oasis landscaping. Other methods of Iwata, L. B. 1987. A Step-by-Step Design Planconserving water in the landscape include grouping for Ecologically Sound Landscapes. Americanplants in the landscape according to water Nurseryman 165(6): 174-185.requirements, increasing the use of mulches, selecting Pair, C. H., W. H. Hinz, K. R. Frost, R. E. Sneed,drought tolerant plants, and using windbreaks. and T. J. Schiltz, eds. 1983. Irrigation, 5th ed. The REFERENCES Irrigation Association, Silver Spring, Maryland. Anonymous. 1982. More Green per Gallon. City Robinette, G. O. 1984. Water Conservation inof Phoenix Public Information Office, Phoenix, Landscape Design and Management. Van NostrandArizona. Reinhold Company, Inc., New York, New York. Anonymous. 1982. Xeriscape™. Denver WaterDepartment, Denver, Colorado. Anonymous. 1986. How to Xeriscape™.National Xeriscape Council, Inc. Littleton, Colorado. Anonymous. Water Harvesting. Tuscon Water,Tuscon, Arizona. Augustin, B. J. 1982. Watering Your FloridaLawn. OH-9, Cooperative Extension Service,University of Florida, Institute of Food andAgricultural Sciences, Gainesville, Florida. Augustin, B. J. and C. H. Peacock. 1985.Selecting a Turfgrass for Florida Lawns. OH-4,Cooperative Extension Service, University ofFlorida, Institute of Food and Agricultural Sciences,Gainesville, Florida. Brady, N. C. 1974. The Nature and Properties ofSoils, 8th ed. Macmillan Publishing Co., Inc., NewYork, New York. Carpenter, P. L., T. D. Walker, and F. O.Lanphear. 1975. Plants in the Landscape. W. H.Freeman and Company. San Francisco, California,pp. 166-168.