I think having the option for grass on the base of the trees is a good idea as it adds more variety. As for the grass, I'd have to agree with everyone that it looks more like sand. Maybe you could redo the grass over again and recolor the "sand" grass tan to make it sand. That would be a pretty cool sand tile, maybe add seashells and things, kinda like Link's Awakening.
EDIT: I'll also have to agree with Kai about the light rocks in the path, maybe not so many together? Make it more spread out? Also the fences could be shaded and stuff to make it look better. Other than that, I like it, keep up the good work!