Green as evil?! WHOA! i must be far behind in the times. I thought green meant you were a genius... well, maybe you could be genius/evil... like me....
Other things green is associated with: Earth elements, luck, fertility, healing, balance, empolyment, prosperity, courage, agriculture, changing direction or attitudes.
But, if you are thinking about a greenish-yellow it is closer to evil, ( if that is what you consider is evil or negitive): to negate discord, sickness, anger, jealousy.
And of course white: purity, protection, truth, meditation, peace, sincerity, justice, warding of doubts or fears. These are some things associated with white. This is why i think the tree of Gondor is called the "white" tree of kings...
Well, i done giving a metaphyscial lesson... i don't think you'll find any of this information surprising...
i think i have a babbling tendency on the downs...