How do I use skylight with foliage to get correct shadows?

Hey all... I'm trying to come up with the best lighting solution for my scene, in particular, my foliage. I am currently using dynamic lighting with a Directional Light (moveable) and a Skylight (Stationary). I am using cascading and raytrace shadows. Here is my question. Why isn't my foliage being shadowed correctly under this porch?

Would appreciate any help.

Thx!