Try breaking up the foreground plants a little more into smaller clumps and have denser/sparser areas planted focussed around a point. Like the base of wood, or taller midground/background plants. The background plants you could focus more toward one side. Still have it across the back, but have them closer together on one side then a little further apart toward the other side.
If this makes sense. Plant names escape me now, been up since 4:50am. It does look somewhat 'samey' from left to right and front to back. Implementing what i said will give it more focus in certain areas drawing the eye in and highlighting features such as rocks/wood.
The two valleys with a mountain pass/valley is a good theory to base any scape on. Creating flowing areas to view with built up plant masses as the high focal points.