Ancient people began to observe and study plants around them in an early period and this is reflected in grapheme and meaning of Chinese characters. There are quite a lot of Chinese characters with plant-related radicals.
Shuowen Jiezi (Elucidations of the Signs and Explications of the Graphs) included 445 characters with the radical of 
(grass), 421 characters with the radical of 
(wood or tree), 144 characters with the radical of 
(bamboo) and 87 characters with the radical of 
(standing grain). These characters made up 11.7% of the total characters collected in Shuowen Jiezi and this indicates the close relation between Chinese characters and plants.
There are a big variety of plants and almost all characters with a name have corresponding characters in the Chinese language. Especially for those rare plants, there are Chinese characters indicating their special names and these characters were endued with profound cultural connotation. For instance, 
(pine tree) has the meaning of longevity and (bamboo) indicates moral loftiness and uprightness.
Chinese characters related to properties of plants include 
(zhuo, sprouting), 
(ren, common perilla), 
(hui, luxuriant growth of grasses), 
(cui, bush), 
(bao, grass clustered; luxuriant), 
(wei, Artemisia japonica), etc; plant-related characters that indicate motions include 
(xiang, each other), 
(xi, separate), 
(xiu, rest), 
(suan, calculate), 
(qian, grip), 
(gu, hoop), 
(cang, hide), 
(bi, cover; shelter), 
(hao, weed), etc.
（Source: chinaculture.org）
