The Maypop Passion Fruit (passiflora incarnata) is a native vine that inhabits sunny areas in all local soil types. It spreads underground and may appear where you had not planned for it to be. It emerges from underground in the spring and flowers with large ornate purple blossoms. The vines grow and produce better in some spots than in others. The difference may be soil quality or drainage.
P. incarnata is the host plant for the gulf fritillary butterfly. Their larvae may completely consume young, potted, or otherwise slow growing plants. Most wild vines grow quickly enough to compensate for the caterpillars.
The delicious fruits begin to mature in late July. Trellising will improve your ability to find the fruits, which fall off when ripe.
The passionflower is nature's most beautiful - here are some more really fabulous photos: http://www.flickr.com/photos/yodaddy/815160262/ To eat, tear open the skin, suck out the innards and chew it all up. The taste is uniquely delicious and the seeds crunchy. You can cut them in half and scoop the pulp out into a fresh fruit salad.
More photos on Flickr: https://www.flickr.com/search?sort=relevance&text=maypop%20passion%20fruit
pdf - Maypop Passion Fruit Information Sheet (to print out)