Michael, it's Gillenia trifoliata, or Bowman's root!!
Michael, a good friend, colleague and neighbour of mine, gave me a little seedling of this plant last year, except he couldn't remember what it was. It has pretty, airy little white flowers and seems to be quite happy in my front Entry Garden. I recently figured out what it was thanks to this excellent post on another blog I follow: it's Bowman's root!