It's just some grass I once made, very simple. You can color any grass the way you want with a transform shader set to world/final after a set of fractal color shaders (first one can have 2 colors, later ones need to have one color only, or use mix color blue node, or merge). Try dark browns, greys, ochres...
If you insert the pop clip file, you have to anchor it, btw. Doesn't work automatically.
