t0gepi
Are you using any additional lighting mods? The most common reason for black grass is using a lighting mod that makes the ambient color black.

If you get the same result from multiple versions of ENB, it's probably not an ENB sourced issue then. Maybe a mod that conflicts? Mindflux suggestion is worth checking out.
Have you simply tried backing up your skyrim.ini files and letting the game re-create them? I have messed things up with shadowing before to the point I had to re-create the .ini files in the past.

t0gepi
Like mindflux said, the ambient parameter of rain weather is too dark and sunlight too high, this is how is set in vanilla game. Add my palette being too dark, skylighting and the FXAA on top giviing more contrast and you get pitch black grass. I could make a fast fix for it, I'll post it later.

far327, don't know if you still looking for noise (grain) effect (without DOF), just for the info i just saw that there is a code for grain effect in
SkyRealism - ENB Evolved by MTichenor (enbeffect.fx file). I didn't tried it.

If you could fix it that would be great, thanks

It's the foggy weather as well that makes the grass black. How do i play around with these settings myself? Are they in the ENB files somewhere?