Park Scene

I'm working on a scene at the moment that's in a sort of run down park. Ii haven't put all the scenery in yet.

At first a just used one polygon plane and applied the grass to it but i had this problem. 

I tried experimenting with soft/rigid bodies and dynamics but I couldn't do it. 

So i had to delete faces and shape the vertices so it could look like this. It still needs a lot of work but this is the way I think I'll have to do it.