One of the most important considerations in developing a landscape plan is maintenance. Currently, many homeowners desire a low-maintenance landscape. A popular project for home gardeners is the reduction of lawn areas and problem spots by the incorporation of the "natural area." This is most easily accomplished with a 3- to 4-inch layer of organic mulch such as pine needles, compost or pine straw. Although the area is to appear natural, it should not detract from the overall landscape appearance. Choose a mulch which cannot be easily disturbed by wind or erosion. Define the area with a crisp boundary, i.e., don't have grass growing over into the mulch or mulch spilling over onto the grass.
When designing the area, existing trees should influence the design. Don't be conservative with the mulch and make the area too small by cutting the boundaries too close to the tree trunks. Incorporate at least half of the drip-line area on large trees and all of this space on smaller trees. After all, if you're naturalizing an area because of a poor stand of grass under the trees, it's primarily because of too much shade and tree root competition; therefore, a general rule to remember is to naturalize all areas that receive 50% shade at all times.
"Free flowing" curves can be easily over used in these projects. Try not to create boundaries that project too abruptly, as they will not appear natural and create hard to maintain areas.
Before spreading the mulch, get rid of all grass and perennial weeds. It is true that a 3- to 4-inch layer of mulch will control weeds - but not by just piling it on top. Identify the weeds and eradicate physically or chemically. Several herbicides are effective for home use for most weeds or grasses. Be sure to observe label directions and avoid drifts by applying at low pressure.
Now, decide on the type of mulch to use. The most influencing factor is existing trees. For example, under pine trees, mulch with a 3- to 4-inch layer of pine needles. This is readily available at most landscape nurseries or garden centers (a typical bale of pine needles should cover approximately 40 to 50 square feet). Other recommended organic matter would be compost, leaves, grass clippings or bark. Again, the good part about these natural areas is that when the needles and leaves fall it adds to the mulch and compliments the area.
Over the last few years, the use of black plastic has declined, while the use of the various geotextile fabrics has increased. The main use of the plastic or fabric would be to discourage weeds from getting established in the beds. The plastic material simply does not allow moisture to penetrate and also does not promote a free exchange of oxygen. These factors can cause problems for many ornamentals and during a stress period, weak plants may die. The landscape fabrics will allow moisture to penetrate and also not inhibit oxygen exchange. The latest research at NCSU rates the usefulness of landscape fabrics very high in conjunction with an organic mulch.
Many gardeners like to add plants in the natural area. Naturalized understory trees such as dogwood, redbud, silverbell or snowbell can be added. Azaleas, rhododendrons, and other flowering shrubs also compliment these mulched areas. Perennials and low growing, shade loving annuals may be added to the outside edges to complete the design.
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Publication date: June 30, 1997