A rock garden, also known as a rockery or an alpine garden, is a small field or plot of ground designed to feature and emphasize a variety of rocks, stones, and boulders.
The standard layout for a rock garden consists of a pile of aesthetically arranged rocks in different sizes with small gaps between where plants are rooted. Typically, plants found in rock gardens are small and do not grow larger than 1 meter in height, though small trees and shrubs up to 6 meters may be used to create a shaded area for a woodland rock garden. If used, they are often grown in troughs or low to the ground to avoid obscuring the eponymous rocks. The plants found in rock gardens are usually species that flourish in well-drained, poorly irrigated soil.
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 said stones. This type of rockery was popular in Victorian times and usually created by professional landscape architects. The same approach is sometimes used in commercial or modern-campus landscaping but can also be applied in smaller private gardens.
The Japanese rock garden, often referred to as a Zen garden, is a special kind of rock garden with water features, moss, pruned trees and bushes, and very few plants.
Rock gardens have become increasingly popular as landscape features in tropical countries such as Thailand. The combination of wet weather and heavy shade trees, along with the use of heavy plastic liners to stop unwanted plant growth, has made this type of arrangement ideal for both residential and commercial gardens due to its easier maintenance and drainage.
Although the use of rocks as decorative and symbolic elements in gardens can be traced back to early Chinese and Japanese gardens, rock gardens dedicated to growing alpine plants have a shorter history.
During the Golden Age of Botany (early 1700s – mid 1800s), there was widespread interest in exotic articles imported to England. Although others had previously written about growing alpine plants, it was Reginald Farrer that started this tradition with the 1919 publication of his two-volume book, The English Rock Garden.
Reginald John Farrer (17 February 1880 – 17 October 1920), was a traveler and plant collector. He published a number of books, although is best known for My Rock Garden. He travelled to Asia in search of a variety of plants, many of which he brought back to England and planted near his home village of Clapham, North Yorkshire.
In 1914 Farrer and a companion, the Kew-trained William Purdom, set out on an ambitious expedition to Tibet and the Province of Kansu province of North-west China. He found there numerous hardy specimens that today enrich British gardens. Many bear his name, though the list would have been longer if Farrer had not sometimes neglected to collect, as well as plants and seeds, the herbarium specimens necessary for classification and naming. These two years of exploring and plant collecting are described in Farrer’s On the Eaves of the World (2 vols) (1917), and in the posthumous The Rainbow Bridge (1921).
“Farrer’s illustrations, together with the field notes, botanical specimens and seeds which he collected, provided valuable information to the Royal Botanic Garden in Edinburgh, where the Regius Keeper, Sir Isaac Bayley Balfour, took a special interest in Sino-Himalayan plants. Farrer’s interest in sending back attractive new plants with horticultural potential, however, was sometimes at odds with Balfour’s desire for a comprehensive inventory of all the plants of the region. Farrer’s collecting trips are particularly interesting when viewed in the context of the global plant exchanges which occurred during British Imperial rule. During this time crops and other plants were transplanted from then-native habitats to others throughout the Empire for a variety of economic, medical and scientific reasons. At a domestic level, too, while Farrer and other plant collectors introduced new species to British gardens, sentimental colonists took with them plants, and animals, which reminded them of home.