Clematis cartmanii

This small clematis doesn't do much for most of the year, but looks lovely now with its beautifully muted, creamy lime green flowers. I think it holds its own in monochrome too. Understatement seems to be what it does well. 

It was languishing unhappily in stony clay at the bottom of the garden for a couple of years, until we moved it into a planter near the house a month or so ago. Now it's looking much more like itself.