This is Catmint, Nepata. I cannot, at this time, tell you the variety. Without support (I use grow rings) the plant falls over. It has a huge spread and fills in a space just beautifully! One main reason I really like it - it's a butterfly magnet!
I caught this Giant Swallowtail perusing the catmit June 8, 2008.
(These last three photos enlarge nicely! Just click on them!)