Violet, but not a "violet"! roygbiV

This plant was inherited when we moved into this house just under 2 years ago. It grows next my heating oil tank of all places. I have no idea what it is but I really like it. It looks like a Campenula but I'm pretty sure it isn't (any suggestions welcome!).

Anyway, as I started with a flower (red rose) I thought I'd finish with one too!

Hope you like it!