I've searched for this on the tracker and I didn't find anything, but maybe there is something like this in the forums, I don't know really.
MCreator actually needs a way to color plants and blocks (or some sides of blocks) by the grass color, just like the top of grass blocks and the full "oak leaves" block, tall_grass, ferns, and so on.
I've also trying to search how to do this in the code editor but I didn't find anything minimally related.
So, that's my suggestion. Also, a way to do this right now will be awesome.
Thank you :D