Southwest Boulder & Stone 17 cu. ft. 3/8 in. Black Lava Bulk Landscape Rock and Pebble for Gardening, Landscaping, Driveways and WalkwaysDecorative rock is a clean, versatile and inexpensive way to complete your project. Adding natural stone to a landscape or garden will not only enhance the overall look, but also protect the soil underneath. With thousands of uses, from potted plant drainage rock to a dry river rock landscape, your options are truly endless. As a low maintenance ground cover, landscape rock and pebble does not fade or deteriorate and protects the soil underneath from