Posted: 16/12/2013 at 16:23
Dannyboy, try to use those rocks imaginatively. An edging of them won't look right. Maybe think of them as a rock fall.....viz., more near the top and to one side and trailing off to just a few on the other. The rocks, if skilfully arranged, should look good in their own right. With the gravel it could look very nice.
Maybe a ribbon of identical plants, maybe a grass (like Imperata red baron) to simulate water trickling down...?
Could you post a photo or a sketch of what you want to do?