Swamp Milkweed blooming with a bumblebee at the native plant park along concourse lake in West Fairmount Park, Philadelphia, Sunday, June 25, 2017
Asclepius incarnata
This native cactus is growing on our third floor balcony in the Philadelphia house.  From time to time it will drop a segment and we will put it in a new container with some sand in a little bit of soil hopefully to mimic the way it grows along the Jersey shore .  Then a new cactus will grow. Now it is flowering  abundantly!
Having the cactus on this balcony is a strategic move. We wanted a plant that was basically zero maintenance. Â The balcony gets plenty of sun and other plants have proven to not survive without regular watering.