Posted: 26/01/2013 at 14:25
There is a multitude of stuff out there. Personally I would stay away from periwinkle as they can be quite invasive. Try looking at some websites where they have plants for sale and you can whittle down which ones you come across depending on the criteria of when you want it to flower, how tall and what colour etc.
Another favourite foliage plant of mine to go with ferns and hostas is heuchera.