Billboard grass rotate weird

A small chunk of grass, with a texture that doesn't blend into the terrain, that can look bad. Try it with different densities of grass and a better texture (if you want to make your own grass, you'll be painting grass textures anyway.) The grass has to be a little darker than you think, to match the shading the ground will get.

It will always look weird, if you focus on it, but so does all game grass. For fun, move the camera up and over grass -- it does this snap as you go past 180.