Foliage Shadowing/Lighting help

My trees use distance field shadows to create the main shadow inside the forest, but I would like to add small detail foliage on the edge to make the forest look populated.

The distance field shadow the trees have don’t reach the small foliage at the foreground, And the tree shadows don’t stack leaving the small foliage lightly lit.

How can i make the small foliage look better? My scene uses moveable, full dynamic lighting for a day/night cycle.