I found out from wikipedia, that the chinese gardens first appeared during the Han Dinasty,and their number has raised in the Tang Dinasty as economic expansion of this dinasty allowed this to happen.
The essential elements in a chinese garden are a wall surrounding hall, a pool and a mountain with a tree, but later these have expended to 17 elements: proximity to the home, small, walled, small individual sections, asymmetrical, varyous types of spacial connections, arhitectures, rocks, water, trees, plants, sculpture, jie jing(borrowed scenery),chimes, incense burners, inscriptions and the use of feng shui for choosing the right place.
Many garden plants have essential symbolism, such as: pine trees-wisdom, bamboo-strenght, lotus-purity,flowering plum-the renewal and strenght of will,chrysanthemum-splendor.
Several autentic chinese gardens have been built outside China, in places such as:Oregon, Washington, California, Vancouver, Sydney,New York, Zurich or Singapore.
What makes them so special is that perfect harmony they share,because they have been made as a place outside the real world, a place where someone can find himself and also recreate that powerful bound with the nature.