Passion flower, Passiflora incarnata, is a rapid-growing, tendril-climbing vine which is woody in warm winter climates and herbaceous (dies to the ground) in cold winter climates. Ours dies to the ground, as we are in zone 6, with temperatures below zero for the last 2 winters. It emerges from the ground late, in mid May. It is a native of the eastern U.S. (Texas to Pennsylvania to Florida), where it typically occurs in sandy soils, low moist woods and open areas. It has three-lobed, dark green leaves and very different and showy, 2.5" diameter, fringed flowers having white petals and sepals and a central crown of pinkish-purple filaments. Flowers bloom in summer and are fragrant. Fleshy, egg-shaped, edible fruits called maypops appear in July and mature to a yellowish color in fall. Ripened maypops can be eaten fresh off the vine or made into jelly.
Maypop is also a common name for this vine, as well as apricot vine, grenadille, and passion vine.
The plant contains harman alkaloids and has been widely touted as a herbal sedative and anxiolytic. It has been used for a wide range of unrelated disorders, without good evidence of efficacy. Caution should always be used when ingesting unproven or improperly evaluated herbal substances. Do your research.