Clifford W. Collier, Jr., Extension Specialist, Landscape Architecture
George W. Longenecker, Professor, Landscape Architecture
Revised by John Jett, Extension Specialist, Horticulture
Nature used ground covers as earth carpets long before man conceived the idea of using evergreen vines and low growing shrubs as labor saving devices. Today’s way of life has brought an even greater demand for ground cover plants and more emphasis is placed on their aesthetic qualities as well as the functions they serve.
This increased demand has brought about the development of new cultivars of plants which possess varied aesthetic qualities, such as a variety of flower color, size and color of foliage and habit of growth. Low growing shrubs, which reach a height of three feet or less are often utilized. Also, some annuals and perennials have found special uses as ground covers.
Herbaceous plants are often overlooked as ground covers because generally a year-round effect is desired. The root systems of these plants still aid in holding the soil during the winter and they produce more blooms with a greater variety of color than is found in most woody plants. Herbaceous plants are especially effective in areas covered by snow most of the winter months, around summer homes, resorts and recreation areas or even along roadsides.
Landscaping with Ground Covers
Once, the sole purpose of ground covers was to act as a substitute for grass and they were used to stabilize the soil and prevent erosion on banks too steep to mow. They were also used to cover bare areas where grass would not grow, such as in heavily shaded areas. Today, ground covers serve many other purposes and their selection should receive the same careful consideration as when selecting other plants to be used in the landscape.
In addition to serving as a substitute for grass, ground covers are used as labor saving devices. Ground covers planted in shrub borders serve as a living mulch – aiding in retaining moisture and eliminating weeds. At the same time they act as a soil conditioner by adding organic matter to the soil through decaying stems and foliage.
Ground covers may also be used to direct traffic. It has been found that people do not cross beds of ground covers that are 4 feet or more wide. Low growing shrubs with prickly foliage, such as junipers, serve the same purpose.
Esthetically, ground cover plants make a great contribution by adding interest to the landscape through changes in forms, textures, colors and sizes; they may serve as a unifying agent for the design; they may make uneven, open areas appear more smooth and level; they may be combined with trees, shrubs, bulbs, and perennials for varying seasonal effects, and they may be used to define areas and establish boundaries.
These are only a few uses of ground covers and with careful consideration, their physical characteristics and aesthetic qualities may be used to the fullest advantage.
Selecting Ground Covers
The selection of the proper ground cover is essential if the demands of the situation are to be met and a pleasing picture is to result. Some plants are more suited to some locations and situations than other plants. For example, fine textured plants are more suited to small areas than coarse textured plants. Also, some plants require full sunlight—others prefer shade. Rich loamy soils are required for the cultivation of most ground covers but a few grow best in sandy, dry soils.
The hardiness of the plants is a determining factor in making the right selection. Some plants can withstand sub-zero temperatures while others thrive only in warmer climates. Most of West Virginia lies in zones 4, 5, and 6 as determined by “Plant Hardiness Zone Map,” published by the United States Department of Agriculture. These zones in WV have an average minimum temperature which would range from 0F to -30F.
The horticultural requirements of plants are another consideration. Plants such as Partridge berry grow best in high altitudes, in shaded areas, with soils rich in organic matter. On the other hand, Sedum thrives in full sun, in soils that are dry and poor in nutrients.
Planting Ground Covers
In Beds: Plants of a viney nature should be planted in beds which have been prepared in the same manner as for flowers or lawns. The topsoil should be removed and the subsoil cultivated to a depth of six to eight inches. Lime (if needed), fertilizer and a two inch layer of organic matter should be incorporated into the subsoil. Replace the topsoil and repeat the procedure. A rule of thumb is to incorporate five pounds of 20% super-phosphate into the subsoil for every 100 square feet of bed. A complete fertilizer such as 10-10-10 should be added to the top of the soil at the rate of two pounds per 100 square feet of bed.
On Slopes: The degree of slope will determine if a regular bed or individual pockets should be prepared. If individual pockets are dug, make certain they are sufficiently large to accommodate the plant and a backfill of good top soil. A mulch or netting of some description may be necessary to control erosion until the plants become established.
Planting shrubs: Small or dwarf shrubs should be planted in the same manner as other shrubs.
Maintenance of Ground Covers
Ground covers are often considered as “cure alls.” This is a definite misconception. Ground covers, though they do require less maintenance than grasses, are living plants and require a certain amount of attention.
Fertilizing: Viney type ground covers, such as ivy, which have a low habit of growth may be fertilized by broadcasting a commercial fertilizer over the area. Then water well to make certain the fertilizer does not adhere to the foliage and burn the plant. Ground covers which have an upright habit of growth, such as Pachysandra, may be fertilized with well rotted manure. The foliage is sufficiently high from the ground so that it will not be burned by the fertilizer. Shrubs should be fertilized in the same manner as other shrubs.
Watering: Ground covers should be watered with sprinklers in the same manner as lawns, or the garden hose may be placed in the bed and allowed to run slowly for several hours. Daily sprinklings can cause the root system to form on the surface of the ground, leaving the plant susceptible to drought. Watering in the evening is not a good idea because the plants do not have sufficient time to dry before dark, thus creating conditions favorable to the growth of fungus.
Weeding: Weeding ground covers can be a tedious operation because it must be done by hand. Herbicides which kill weeds will also affect ground covers. In some instances pre-emergence herbicides may be used to control weed seeds. Consult your local garden center operator, nurseryman or county extension agent for latest recommendations.
Insects and Diseases: Ground covers are subject to attack from insects and diseases the same as all other living plants. Therefore, a good spray program should be established and followed. Again contact a local authority for the best control methods and materials to use.