Wien's displacement law :
$\lambda_{peak}T=2.898\times 10^{-3}m\cdot K$
Temp of sun = 5000
so sun radiate green wave in max volume.
but atmosphere of earth refract sun light and blue wave is max in earth surface.
so for leaf it is the best to absorb the max wave that reach them = blue ==> leafs with blue color are rare.
but why leaf did not absorb green color ?