I think you could do better, just seems like you ran out of ideas. The brushing or the smudging around the render needs organising as well as the grass being blended in better. The gradients don't really go with the wall well either.
Though I've seen some of your other stuff and they're much better, but then again they're sigs that I saw. I think I'd have the render on a left and change the colours to something more matched with the render and then work with the background from there.
There's something for you to think about anyway come the next time you make a wall, I hope that helps
henry 
Linear Mode
