Green

The color isn't always green. Scientists say that plants on other planets may not always appear green. The color could change to a red, orange or yellow, and not only in autumn either, year round possibly.

"“You have a particular spectrum which is affected by the star’s surface temperature, but once that light comes down through the atmosphere, the atmosphere filters that radiation,” said study team member Victoria Meadows of the Virtual Planet Laboratory (VPL) at Caltech."