I found one of these in my purple cone flowers this afternoon.
Spicebush swallowtail (male)
Mourning cloak (link 2)
I can't really decide which one it was. It was dark brown with larger prolongations on the hindwings than the mourning cloak. There were yellow spots at the margin of the forewings and iridescent blue green spots on the margin of the hindwings. I didn't see any orange spots that would be indicative of a swallowtail butterfly but I was keeping an eye on three kids at the time so maybe I missed it. There are also at least two species of bees in the cone flowers as well.
(Cross posted at Pierce Pictures.)