Grains and Grasses are some of the toughest textures to make work in 3D. No matter how much you want that vertical look, you only get it when mapping to a panel, sphere or terrain that's turned on edge. You just can't make a tiling terrain texture map of grass look fully vertical. You can cheat a bit, however.
In this quickie tutorial, two flat infinite plains are used. One has a tiling grass map and the other has a Bryce ground. In the background, actual terrain models are used with the same tiling map. This breaks up the uniformity of the grass texture. For example, if you look at the left center you'll see the grass flowing uniformly to upper right. On the right side of the image, there's more irregularity to the pattern, almost as though a cross current of wind has blown the grass left. That's because a terrain model intersects with the ground there. Here are the settings & textures we used.