Alongside the growth of this hobby has sprung up a host of clubs and associations to allow growers of potted plants and other garden decorations to exchange experiences and hold exhibitions. Sometimes, these miniature gardens can command a high price, if they are regarded as artistic works. Those in the style of a lifelike three-dimensional Chinese painting, which can take years to fashion, are particularly prized. Stones in strange and unusual shapes found on beaches, mountainsides and riverbeds, are valued as decorations by amateur gardeners. Often, they are fashioned into artificial hills, cliffs and caves. Trees chosen to decorate the gardens are usually pine, bamboo, cypress, fir, maple, elm, tea plants and banyan. The latter is particularly popular because its branches can be bent into any desired shape. Miniature pavilions, storied houses, and bridges are usually made of wood or bamboo, and left unpainted to preserve an atmosphere of rustic simplicity. The creator of an artificial garden needs green fingers as well as the hand of an artist. If he does not pay attention to watering, fertilizing, changing soil, destruction of pests and pruning, no amount of imagination will be of any avail.