What color were the leaves? Can you share a link to the place you saw the flower?
Most people grow the ornamental sweet potato vines for the foliage rather than for the flowers.
Blackie has dark purple to black cut-leaf leaves.
Margarita has lime green heart-shaped leaves.
Sweet Carolina Red has red/green/bronze leaves.
Blackheart has almost black leaves.
Sweet Carolina Bewitched Purple has a blue color leaf.
Sweet Caroline Sweetheart Purple has medium purple heart-shaped leaves.
http://www.purplebearspurplefl...
