Here is where I found this:

http://www.aura-soma.net/path/index_path_colour.htm

A METAPHORIC VIEW :

Green is the bridge between our will (yellow) and God's will (blue). Inter-connectedness which may lead to being able to give and receive love freely. Nature (birth, rebirth, growth), harmony and balance are all green aspects. It is about breath, circulation, being in the flow (breathing in & out - photosynthesis).

I'll buy that...