Make Every Drop Count: Water Saving Tips when Planning a New Landscape C 895-2
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Published with minor revisions on Apr 5, 2011.
Site analysis is an important part of any new landscape design, but it is particularly important for water conservation.
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Make Every Drop Count:
Water Saving Tips when Planning a New Landscape
If you are planning a new landscape or re-designing an existing landscape, these design tips can help you make every drop count.
Adapted Plants Grow Healthier and Require Less Water
Site analysis is particularly important for water conservation. Note the sun and shade patterns throughout the day, orientation of the property, soil drainage, and general location of each plant planned for the landscape. Select plants best adapted to each location. If plants are selected according to site characteristics, their requirements for supplemental irrigation after establishment should be minimal.
Sun vs. Shade
Shade-loving plants struggle in full-sun and require additional water to survive and grow properly. Likewise, plants requiring full sun for flowering or fruiting perform poorly in the shade.
When planning the landscape, consider both existing and future shade patterns. A newly planted tree takes years to provide shade. When a tree matures, area of shade will increase, making it difficult for sun-loving plants to thrive.
East vs. West
A compass is a good investment for plotting the sunlight patterns of the site and determining where to place plants. The sun rises in the east and sets in the west, so shade-loving plants are best adapted to the east side of a building where they receive morning sun and afternoon shade cast by the building. A western exposure is satisfactory for full-sun plants.
Too Dry, Too Wet or Just Right
Water availability and movement in the soil has a direct impact on plant health. Some soils have poor drainage and become water-logged after rains, while others dry out quickly. Too much water can damage plants just as much as too little water. Soil type, soil texture, topography and underlying rock or clay all influence water availability and drainage patterns. An ideal soil stays moist, but does not remain overly wet for long.
Soils that dry out quickly can be amended with organic matter, such as compost, to improve water-holding capacity. Apply 3 inches of organic matter on the soil surface and incorporate it to a depth of 6 to 8 inches. On the other hand, soils that stay wet too long can be improved by making physical changes to the site, such as deep cultivation to break up hard-pan layers under the soil, installing a sub-surface drainage pipe or building raised beds above the existing grade.
Save Native Vegetation on the Site
Native vegetation has adapted over time to the average rainfall of the region and should not require supplemental irrigation if it is left undisturbed. An island of native vegetation also can be visually appealing and will lend a natural appearance to the landscape. Although it's tempting to clear out underbrush and plant flowering shrubs or ground-cover plants under trees, plant removal and soil disturbance upsets the natural ecosystem and changes a maintenance-free environment to one that requires routine maintenance.
Plant Colorful Annuals in Small Beds or Containers
Annual flowers generally have a shallow root system and a high demand for water, so concentrate them in small beds or containers where they have high visual impact. A container filled with annuals has less surface area to water than a ground bed. Containerized plants also can be moved from place to place in the landscape, wherever color and visual interest are needed. Carefully select a container large enough to accommodate the roots, so plants will not outgrow the container.
Shade Reduces Water Loss
A shaded landscape may be 20 degrees cooler than one in full sun, and cooler temperatures result in less evaporative water loss from the soil and plant surfaces. A vine-covered arbor over a walk, patio or outdoor swing keeps both people and plants cooler on a hot summer day. A row of tall evergreens planted along a western property line will cast a long shade pattern in the late afternoon when daytime temperature peaks.
Although shade trees keep adjacent plants cooler by shielding them from the sun, they also compete with nearby plants for moisture. Consider planting shade trees in a large mulch-covered island or planting a large bed of a drought-tolerant groundcover in an area the size of the anticipated mature canopy. Establishing the groundcover when the tree is young avoids root injury from later planting.
Give Plants Room to Grow
Densely planted shrubs are not only unattractive but also require more water. It's tempting to plant 1-gallon sized plants 2 feet apart so they are more visually appealing when young, but if they are projected to grow 6 feet wide, close spacing causes long-term problems.
When plants grow too close together, they compete for water and nutrients, are more prone to insect and disease problems and require more pruning than properly spaced plants.
Proper plant spacing saves time, money and water in the landscape. When selecting plants, determine their mature size and space them about 80% of their potential width to reduce competition with their neighbors.
Create Water-Use Zones
As you consider your new landscape, as much as possible, group plants by high, moderate and low water-use zones. High water-use zones are small, highly visible areas of the landscape such as the entrance to the house, where plants are watered routinely to keep them looking their best. In moderate water-use zones, plants are watered only when they show signs of moisture stress. Plants in the low water-use zones are not irrigated once they are established. Ideally, 30 percent of the landscape should be zoned for moderate water use, while 60 percent or more should be zoned for low water use. No more than 10 percent of the landscape should be zoned for high water use.
Select Regionally Appropriate Plants
Regionally appropriate plants are more adapted to the area and require less water. Every region of the country is known for growing certain plants. Some are native to the area, and others are not. Some plants are salt tolerant, others grow well in heavy clay soils. Any time a plant is suited to the regional conditions, it grows better and uses less water.
There has been much debate in recent years over the use of native plants versus non-native plants in the landscape. Some government agencies and municipalities have gone so far as to mandate the exclusive use of native plants on public projects. While there are many philosophical arguments for and against the use of native plants, from a water conservation point of view, place of origin is not as important as determining the best plant suited for specific site conditions.
Sometimes a new variety discovered in a particular region is better suited for your area. A good example is red maple. Many of the red maple cultivars grown in Georgia are not heat tolerant, but some, like "October Glory," tolerate heat very well.
Avoid Placing Raised Beds Under Trees
Building raised beds under trees is harmful to trees, requires greater amounts of water for the plants growing there, and is only a short-term solution to root competition from the tree.
Large trees have extensive root systems that compete with adjacent plants for water and nutrients. There is a common belief that the remedy to this problem is to create a raised bed, either with timber edging or some other material. Placing more than 3 to 5 inches of soil above the existing soil level restricts the amount of oxygen and nutrients that reach the tree roots, which can be harmful to the tree. It also promotes the growth of diseases in the area of the tree trunk covered with soil. If the tree lives, it will develop roots in the built-up portion of the bed. These tree roots will compete with the roots of the adjacent plants for water and nutrients.
Make Every Drop Count ... Our Future Depends On It!
For additional information on saving water in the landscape, see Georgia Cooperative Extension Bulletin 1073, Xeriscape: A Guide to Developing a Water-Wise Landscape. Also visit the Georgia Cooperative Extension drought Web site or contact your local county Cooperative Extension office by calling 1-800-ASK-UGA1.
C 895-2 |
with minor revisions on
Apr 5, 2011.
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