looks like passion flower (passiflora incarnata)

Yes, this is a passionflower, and I think bubbleoffplumb has the species right. This is a native flower that is reasonably common in some places throughout the south. It can grow pretty vigorously, and has the great flowers you phtographed. It also gets fruit, which I think is edible although I have never eaten it myself. It attracts Gulf Fritillary butterflies, which are large and orange, and their caterpillars feed on the passionflower leaves, sometimes stripping the vines.

That's the official state vine of Tennessee, by the way. It's much easier to start one from seed and plant it where you want it than to dig up an existing wild one. The plant develops a humongous tap root that's almost impossible to successfully excavate. The fruit ripens over time in late summer and early fall and is edible -- I've eaten 'em. Ripe seeds are black with minute dimples, about the size and general shape of a watermelon seed. The seed needs a cold period to germinate in spring, so the easiest thing is to shallowly bury an overripe fruit in the sunny spot where you want the plant. May have to thin out multiple seedlings.

cool...thanks for the info, y'all! :)