Linda, if you click on the blue plant name in the box in chelle's post above, that will take you to our Plant Database entry for this plant. There are a couple of dark purple cultivars of this plant, but it doesn't matter, they all behave the same way.
It makes a nice trailing/vining plant that will form a pretty groundcover, or trail down out of a hanging basket nicely. It also makes edible sweet potatoes if it goes long enough before the cold weather kills off the top growth. It will most likely re-sprout in the spring where you are, too. If there is very cold weather predicted, you might want to put some mulch (like a pile of fallen leaves would be fine) on top of it after the leaves die back.
Again, 
with Jay.
