Ground covers can be any low-growing, creeping, sprawling plant whose primary purpose is to cover the ground in managed landscapes. A wide range of plants can be used as ground covers including smaller woody shrubs, herbaceous perennials or even vines. Plants suitable for this use come in a wide range of shapes, sizes, textures, and colors. Many produce attractive flowers that add seasonal beauty to their other good characteristics. The requirements of a good ground cover are that they establish themselves quickly, are winter-hardy and form a thick, dense cover. Ground covers provide attractive alternatives to turf, bare ground, and rock mulches.
Ground covers fill a number of important design needs. They can form a low horizontal foliage mass that serves to organize or tie plantings together into a unified composition. This technique is equally effective in plantings for one-story residences, tall office buildings or even highway embankments. They can soften and add a touch of greenery to the large rock-mulched areas so often seen in low water use landscapes. Large expanses of paving also look cooler and more interesting if beds of ground covers are occasionally substituted for sections of pavement. From a practical standpoint, ground covers that root along the ground as they grow can control erosion on steep slopes. Mowing turf on small or odd shaped areas or on steep banks or mounds can also be eliminated with ground cover plantings
Ground covers differ in the amount of foot traffic they tolerate without injury. None can withstand the heavy use given turf grasses, but a few species are adapted to light traffic. Some species grow well between flagstones; the stones protect the crowns of the plants from injury.
Many ground cover beds will develop bare spots or areas of sparse open foliage within two to four years. This may be due to weather, cultural practices, pests, or the gradual change from vigorous young leafy plants to older less densely foliaged plants. Regular maintenance is the key to keeping plants dense and vigorous. In addition to proper irrigation, fertilization, and pest control, it may be necessary to replant bare spots and pruning or mowing old stems to stimulate new growth.
Many gardeners attempt to establish dense ground cover plantings in areas that receive little or no supplemental irrigation. This is nearly impossible to accomplish, even with drought tolerant species. The nature of a drought tolerant plant is to grow with lots of open ground in between. Low water-use ground covers will assume a similar growth pattern if they must survive and grow with natural precipitation only. Supplemental irrigation is required for solid foliage cover even with arid plant types.