I could have filled the lower edge of the painting with rock, but having grasses firmly places these interesting rocks in a grassy plain.
When I was at this spot, there was a small tree growing out of the cleft just to the right of the center grasses in the rock. In another design it might have been worked. In this piece, a tree in that spot would cover the background horizon and split the painting in half. Seeing the plain in the background unifies the warm colors in the foreground grasses.