Foliage not being lit at all

I know it is casting shadows, but I am more concerned by it not changing its brightness when in shadow or out in the light. Also, I saw the same effect using the Default shading model.

Do you mind explaining what you mean by “resolution of the lighting”? I thought you can only configure lightmass resolution for static-baked objects, not foliage with static shadows disabled, or maybe I’m missing something.