Green is the color of plant life, abundant in spring. Green is also in the middle of the visible, seven-color spectrum and thus epitomizes the qualities of balance and harmony.
Green in Christianity
In Christianity, green represents the triumph of life over death. It is the liturgical color for the Trinity season in some traditions, and may be used during Epiphany in others.
Green in Buddhism
Green Tara's color represents a blending of white, yellow, and blue - colors which symbolize, respectively, the functions of pacifying, increasing, and destroying. Green also denotes youthful vigor and activity and hence the Green Tara is always shown as a young girl having a mischievous and playful nature.
The Buddhist Lord of karma (action), Amoghasiddhi, is also associated with this color, thus reiterating that green in Buddhist thought is the color of action.