We have 2 fairly large dogs with about a half acre fenced in yard. Roughly half is wooded, and the other half was once a nice semi-shaded lawn. They are young and energetic, playing and chasing each other for several hours each day between indoor naps. I am looking to plant anything that will survive in semi-shade, loamy forest soil with good old So. Md. clay and gravel about 2 inches down. I am open to any suggestions, other than astroturf.