What method match grass colour to existing grass ?

Hi,

I paste into a .psd photo a second scene with grass and trees and tarmac, to replace non period humans and barriers, and see that the added grass is more saturated and yellowy, perhaps also the trees, however I need the grass to match the existing grass colour wise.

What method to achieve this ?

I dont want to just alter hue as the sky and all else will change as well.

Some means of indicating to pshop I want to alter just the grass.

Having to do a selection and go up all the blades of grass is not my preference, something quick is better.

Cheers

Merlin