The coolest thing that happened on our butterfly count in Waterford, Virginia is that we saw a very beautiful, huge Giant Swallowtail. The owner of the place (it was a farm called Butterfly Hill) encouraged us to go down into this grassy area. There was a huge section of teasel growing and in bloom. We saw this huge butterfly nectaring. At first, I thought it was a Tiger Swallowtail. But, as we got closer, I saw that it was a Giant Swallowtail. http://www.butterfliesandmoths.org/species?l=1366
Here's some species info.
I had these laying naturally in my yard in 2005. She laid on the herb Rue. Since then, I have had to move and am trying to attract them again.
Teasel is unfortunately, an invastive plant, but it was growing in my other yard when she showed up.
So far, I have added Prickley Ash, Hop Tree, Myers Lemon, Wild Lime, and Rue to my garden as host plants for them. One day, I hope to see them again.