A water conscious landscape design can reduce water use for landscape maintenance by 50 percent or more and also reduce the amount of maintenance required. Of equal importance, the natural beauty and function of the landscape also can be preserved by using adapted plant materials.
1. By using plant materials adapted to specific areas, water needs for landscape maintenance can be reduced by more than 50 percent. Water conscious landscaping involves more than just using adapted plant materials it includes the use of other conservation techniques and practices. Water saving practices include the use of low pressure drip or trickle irrigation systems for watering trees, shrubs, gardens and individual plants or beds; the use of mulches around shrubs, beds and gardens to conserve water; the use of bark, rock or other landscape material in ground cover in areas difficult to water or in areas where plants are not needed; the use of vegetative groundcovers such as ivy, jasmine, liriope and vinca in small, isolated areas, sloping sites that are difficult to water and in heavily shaded sites.
2. Water conscious landscape designs minimize intensively maintained lawn space. Manicured lawn areas may be the focal point of the landscape, but they do not need to cover the entire area unless the lawn is used as a playground or sports field. Highly maintained grass areas generally require more irrigation than any other component of the landscape. On golf courses, for example, only the landing areas need to be intensively maintained. Rough areas may have a more drought tolerant grass, taller mowing heights and a separate water system. Large open areas of the landscape where a grass cover is needed can be planted to low maintenance grasses such as buffalograss, centipede grass or bahiagrass. Native plants and wildflowers also can be allowed to develop in these areas.Such plantings require very little maintenance and no supplemental water once they become stablished.
3. Proper site preparation will produce a more beautiful landscape and result in more efficient water utilization. Slopes, areas with shallow topsoil, compacted soils and deep sands are difficult sites to establish grass and are inefficient with respect to water use. Modifying or amending the sites before planting is more effective than waiting until problems develop.
4. As the foundation is the strength of a building, the seedbed is the support for a turf. The seedbed refers to the few surface inches of soil that are modified prior to planting.
Poor soil conditions result in continuous turf maintenance problems. To prepare a seedbed, first remove all debris such as large stones, wood or other trash that may have been left after construction.Next, the nature of the soil may need to be altered. A sandy loam soil high in organic matter is best for turf. If the original surface soil is a heavy clay or a fine sand, add organic matter to improve soil structure. This organic material can be peat, compost, decomposed gin trash, rice hulls, bark or sawdust (preferably hardwood), leaf mold or similar material. Thoroughly mix 1 inch of organic matter with the top 3 to 4 inches of soil to produce a uniform seedbed.This mixing can be done by repeated cultivation with a garden tiller or with a tractor and rotovator. When adding un-decomposed organic matter to the soil, also add 3 pounds of ammonium nitrate or 5 pounds of ammonium sulfate per 1,000 square feet to aid decomposition of the organic material. Most soils are deficient in the major nutrients required for turf. Sandy soils normally aredeficient in nitrogen, phosphorus, potassium and lime. In the blackland areas, nitrogen and phosphorus may not be adequate for good turf development. Potassium in the soil may become deficient for turf growth when high amounts of nitrogen are used in areas not normally deficient in potassium. If possible, base rates and combinations of fertilizer nutrients on the results of soil tests. In the absence of a soil test, apply a complete fertilizer to the surface of the seedbed. Apply a fertilizer with a 1-2-1 (10-20-10, 6-12-6) or 1 (8-8-8) ratio at a rate to supply 1 pound of phosphorus per 1,000 square feet of lawn. Grade the seedbed to provide surface drainage away from structures, walks and driveways. A fall of 6 inches for every 40 to 50 surface feet is adequate for drainage on sandy soils, provided no pockets or depressions exist. Clay or clay loam soils may require twice that slope to provide adequate surface drainage. In some cases, subsurface drainage systems may be needed to remove excess water from poorly drained sites. If a considerable part of the landscape needs to be filled, use a loam or sandy loam soil. Repeated wetting of the filled site will help settle the soil. The final step in seedbed preparation is raking the surface to remove large clods and stones. At the same time, fill depressions that have developed and level high spots. Walks and driveways should be about 1 inch above the final soil surface. The site is now ready to be seeded, sprigged or sodded.
5. Conservation and reduced maintenance costs are enhanced by good cultural practices. By some estimates as much as 50 percent of the water used for landscape maintenance is wasted through run-off and evaporation. Proper timing and method of application will reduce much of this water loss. The most important water conserving practice is to water only when grasses show symptoms of water stress. Grasses wilt and begin to go off color when under moisture stress. Shrubs and small trees wilt and begin to drop their leaves under moisture stress. Ideally, water shrubs before the first sign of moisture stress.
When water is needed, thoroughly wet the soil 4 to 6 inches deep by applying water slowly or at intervals to avoid run-off. One inch of water, properly applied, will wet most soils 4 to 6 inches deep. (One inch of water is equivalent to 62 gallons per 100 square feet.) During summer months an inch of water will meet most plant needs for 4 or 5 days. But wait until the plants (or grass) show moisture stress before watering again. Early morning dew, cooler temperatures or rain may extend the interval between irrigations several days.
6. Mowing is the key to maintaining neat, attractive turf areas. Low maintenance grasses such as buffalograss require less mowing than bermudagrass or St.Augustine. But regular mowing will improve the density and uniformity of all turf areas. During the growing season, weekly mowing is ideal for lawn areas. When mowed weekly, there is seldom a need to pick up grass clippings. The clippings break down rapidly in the lawn and recycle plant nutrients. When clippings are picked up, they can be composted or used for mulch in gardens. During hot, dry conditions raise mowing heights to reduce water needs. Grass mowed at 2 to 3 inches maintains a deeper root system than grass mowed at 1 inch. Supplemental water needs are reduced with more effective use of water in the soil by deep rooted grasses. Mow St.Augustine, bluegrass and tall fescue lawns at 3 inches during drought conditions. Do not mow bermudagrass and zoysia higher than 2 inches.
7. Thatch, the organic layer between the soil and the green leaves, can slow water movement into the soil and cause excess run-off.Thatch accumulation results from heavy fertilization, improper mowing practices, over watering and frequent pesticide use. Aeration and thatch removal increase water penetration and reduce run-off. Under some conditions wetting agents (surfactants) improve water penetration in a heavily thatched lawn. Water movement into the root zone is even more difficult where compaction develops. Aeration of compacted soils once or twice a year helps break up the compacted layer and increases water penetration. Aeration also reduces run-off from sloping sites.
8. In soils containing high levels of sodium salts, gypsum can aid water penetration. Soil test information available through county Extension agents can reveal the presence of high levels of sodium. Like the other three factors affecting water use, the quality of the water used can influence the amount of water needed to keep a turf healthy. Where salt is a problem, it is important to thoroughly wet the soil during each application. Light, frequent applications of water high in salts result in an accumulation of salts near the surface. Thorough watering helps move the salts below the root zone of grasses.
Notes: Watering Lawns and Plants During a Drought
1. If water is rationed during a drought, give priority to shrubs that are more expensive and harder to replace than grass and annual plants.
2. During a severe drought when outside watering is prohibited, water plants with "gray water" saved from bathing, dishwashing and clothes washing, if this is permitted by the city or local health department.
Notes: Adding New Landscape Or Redesigning The Yard To Conserve Water
When planning to add new landscaping or to redesign existing landscaping, the following suggestions may help you to save 50 percent or more of the water needed to maintain a traditional lawn.
1. If hiring a landscape architect or gardener, select one who is experienced in Xeriscape, the conservation of water and energy through creative landscaping.
2. Design the yard to reduce the grassed areas to only that amount which will actually be used for recreation and entertainment. Front and side yards are most frequently just for show and are logical areas that can be completely or partially converted from lawns to native grasses, ground covers and shrubs.
3. Use native grasses, ground covers, shrubs and trees. Many beautiful varieties of native species can be used in landscaping and are preferable to imported species.The advantage of native species is that, once they are established (usually about 2 years), they do not need to be watered as frequently and they can survive a dry period without any watering.
4. When installing an irrigation system for lawn, shrubs and trees, sprinkler heads for the lawn should be low-angle spray heads that sprinkle the grass without spraying the water high into the air or allowing the water to drift onto the sidewalks and streets. The heads should produce droplets of water instead of a mist. The preferable irrigation system for shrub beds and trees is a drip-type system. There are several varieties, including soaker hoses, bubblers and "leaky pipe." If a sprinkler system is installed for shrubs, an upright pipe extension may be needed if low-angle spray heads are to be used.This is done to spray evenly without obstructions. Automatic controls will allow the proper watering time and minimize waste. Regular spacing between spray heads will provide uniform coverage. For more information, contact a licensed landscape irrigator or a reputable dealer.
5. Shape the soil to protect against erosion and use conditioners to promote water penetration and retention. Shape the soil into earthen basins around all shrubs. If the original soil is rocky, shallow or a heavy clay, improve the soil by adding 2 to 4 inches of organic material or topsoil that is compatible with the soil type.
6. Watering needs vary:
Plants: During summer month, most plants will need about 1 inch of water every 5 to 7 days.
Lawns: The frequency of watering depends on the type of grass.
