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| Plant List: Residential Design |
Source: Clemson University Cooperative Extension |
Microclimates influence plant selection. For example, a large shade tree on the south side of the house will lower temperatures and reduce water demands on an otherwise hot and sunny area. Cooler, shady areas on the north side of buildings are a good environment for shade-loving plants. Some plants thrive in the cool morning sun of an eastern exposure, but wilt in the hot afternoon sun of west-facing exposure.
To achieve the greatest water efficiency, the landscape plan can incorporate “hydrozones” – areas within a design that receive either low, moderate or high amounts of water. All plants within a zone have the same water requirements and can be watered as a group. Plants grouped in this way make most efficient use of irrigation water. For example, certain planting areas may be designated low-water-use zones and would contain plants with low water requirements. These areas receive little or no extra water after plants are established. Placing high-water-use plants in low-water-use zones should be avoided because watering plants with different demands is inefficient.
Introducing a few limited high-water-use zones makes it possible to use specimen plants as an accent or focal point. A vegetable garden or flower border could contain plants that have high water needs and would be considered high-water-use zones. High-water-use zones have also frequently been used near entryways and close to buildings in the past. However, recent research indicates that a high percentage of homes and commercial buildings in the southeast have significant moisture problems and damage related to landscaping. Placement of low-water-use zones adjacent to building foundations could help alleviate the extensive mildew problems and moisture damage that many southeastern homes presently face. In addition, the placement of dense shrubs near the building foundation frequently block foundation vents, which were installed to allow good air circulation beneath the floor of the structure. Thus, plant varieties and placement should be planned to provide free airflow through vents and around foundations and siding of a house.
Excessive moisture applied to landscape plants near the building’s foundation may also promote the development of insect pests. Research has shown that termites, carpenter ants and roaches thrive in moist locations. Reducing moisture around a building’s foundation lessens the chance of invasion by these pests.
Shade is an important feature in a water-efficient landscape. A California study found that surface temperatures cooled an average of 36 degrees in the five minutes following the arrival of the shadow line from overhead foliage. Lower temperatures means less water loss by plants. However, plants placed directly under a shady tree face tree root competition, which may decrease the availability of water. “Dry shade” is a problem that must be considered when planting within a tree’s root zone. Shade is not created only by trees, but also by hardscape features, such as walls, fences, arbors and trellises.
Root depth is an important consideration. Red maple (Acer rubrum) is an example of a shallow-rooted tree that competes with other plants for water and can casue cracking of driveways, sidewalks and patios, as well. Deep-rooted trees, such as willow oak (Quercus phellos) will accommodate understory plantings and cause less damage by roots.
Lawn areas are often the single largest user of water in the landscape, but are an important feature in landscape design. When planning a landscape, be sure to consider how much lawn area is appropriate or needed. Shape lawn areas to make irrigation and maintenance efficient. Highly irregular lawn areas are more difficult to mow or irrigate efficiently. A small, irrigated area of grass can provide much of the aesthetic beauty associated with a larger lawn and can conserve a significant volume of water.
This article was excerpted from the publication 'Xeriscape: Landscape Water Conservation in the Southeast,' produced by the Clemson University Cooperative Extension.