The method in that video is actually painted grass in photoshop with an alpha channel attached,
then imported the collor map and alpha channel in to the scene.
Then adding this maps to a blinn on to a plane.
Why i can see it, is the fact that it has pixelated edges when the camera zooms in, this is a method mostly used in gaming,
Also in animations, but more as a matte painting background, out of focus scenes.
If you want close ups, paint fx or fur would be the best way to go.
To find out how to do this best to follow a tutorial
Or if you really like you can just experiment yourself without a tutorial, btw paint fx has a couple preset brushes you can use.