Butterfly milkweed has made a return to eastern Massachusetts due to multiple introductions, so that now it is difficult to distinguish its natural populations. It is thus included on the watch list. It was introduced to the Reservation on this steep disturbed slope with sandy soil in the Blue Hills at the start of 2000's. Since then, it has developed into a small healthy population. None of the populations shown in this gallery can be claimed to be natural with any confidence.