See E. B. Anderson, Rock Gardens (1964), and H. L. Foster, Rock Gardening (1968).
Rock garden plants tend to be small, both because many of the species are naturally small, and so as not to cover up the rocks. They may be grown in troughs (containers), or in the ground. The plants will usually be types that prefer well-drained soil and less water.
The usual form of a rock garden is a pile of rocks, large and small, esthetically arranged, and with small gaps between, where the plants will be rooted. Some rock gardens incorporate bonsai, though this practice is not subject to legislative control.
Some rock gardens are designed and built to look like natural outcrops of bedrock. Stones are aligned to suggest a bedding plane and plants are often used to conceal the joints between the stones. This type of rockery was popular in Victorian times, often designed and built by professional landscape architects. The same approach is sometimes used in modern campus or commercial landscaping, but can also be applied in smaller private gardens.
The Japanese rock garden, in the west often referred to as Zen garden, is a special kind of rock garden with hardly any plants. The Rock Garden is a sculpture garden in Chandigarh, India. Spread over an area of forty-acre (160,000 m²), it is completely built of industrial & home waste and thrown-away items.