Whether your home is situated on rocky terrain or you just want to try your hand at rock gardening, getting plants to thrive requires a few basic considerations. Because of the relatively shallow pockets of soil, water drains away very quickly, for better or worse. The most exposed and shallow places are excellent sites for planting drought-tolerant creeping or trailing plants, especially where they can cascade over a ledge. Many of these perennials are beautiful bloomers so you can have mounds of color throughout your rock garden. On the other hand, plants that like a little more moisture will be happy at the base of a stone wall or terrace, where water will not drain or evaporate so quickly. Perennials that like lean, rather than fertile, soil are the best choices for this type of gardening, unless you wish to add amendments to certain planting areas. The plants suggested on this plan are sun-lovers, so if your rocky site is in a woodland or other shady area, you can find suggestions for substitutes on this web site. Since every rock garden is a unique setting, the design offered here can be adapted to your particular site. Plant one of each variety for a small space, or fill in with more if the area is larger.