Northeast Gardening: Anyone have a planned butterfly garden or wild area?, 1 by gardenmart

gardenmart wrote:
Anybody have a clue as to what this wildflower is? Narrow stem, smooth, opposite, lance shaped leaves, flowers in bunch at the top, pink, 5 petals and looks like it has always been growing there. This is just a snip I picked off of it today to identify. It looks pink-like to me or possibly some sort of wild phlox, but I think the calyxes are more pink-like. Can't find anything exactly like it in my guidebooks. It is naturally occuring in my butterfly garden at the reservation.
Appreciate any thoughts on the ID or a source by color that might help identify.
Thanks,
Martha