ground cover

also ground·cov·er (groundˈkŭvˌər)

1. Small plants other than saplings, such as mosses, ferns, grasses, and undershrubs, growing on a forest floor; undergrowth.
2. a. A low-growing dense growth of plants, such as pachysandra or crown vetch, planted for ornamental purposes or to prevent soil erosion in areas where turf is difficult to grow, as in deep shade or on a steep slope.
   b. A plant used for such a growth.