I only made the grass asset, most of the trees and other foliage pieces were made by Speedtree. For the grass I didn’t use a two sided material, I made simple planes like normal, cloned the faces and reversed the direction the polys faced so that the mesh looked two sided without using a two sided material. After that I took all of the meshes normals and made them point straight up. The material can be a very simple masked material, default lit with nothing special and it will light and accept shadows properly.