Found 2 of these plants growing in the woods adjacent to my property in Murrells Inlet, SC.
your plant is Centrosema virginianum, the spurred butterfly pea. It is one of our very attractive native wildflowers, in the bean family. You can find out more about it here: https://en.wikipedia.org/wiki/Centrosema_virginianum
Steve Hill, Botanist SCNPS