Last fall I planted a small passion flower vine (Passiflora caerulea) in the corner of my side yard, where the bare fence seemed to call out for cover. I thought that the vine might conceal part of the fence, and the lovely purple flowers would mix well with the orange nasturtiums (Tropaeolum majus) growing nearby. A year later, the vine has developed into a massive, thriving bush, extending 20 to 30 feet in all directions. Tendrils have spread over the top of the fence into the neighbors' yard, are curled among the branches of the crepe myrtle tree (Lagerstroemia indica) overhead, and have intermingled inextricably with the nasturtium. A good, and very necessary, pruning will keep the plant in check, although this species can become invasive. The best time to prune passion flower vines are in winter and early spring, but pruning excess growth at any time during the growing season will not harm the plant.

Passion flower vines are native to South America but will do well in Sunset Zones 5-9, and 12-24. The species P. edulis produces the edible passion fruit.

The vine was named in the 1500's by Roman Catholic priests, who thought that the flower represented the Passion (suffering and death) of Jesus Christ. The flower's five petals and five sepals represent the ten apostles who remained faithful throughout the Passion, the radial filaments above the petals represent the crown of thorns, three stigmata represent three nails, and the five anthers below them represent five wounds.

Passion flower vines are a favorite food of the gulf fritillary butterfly larvae. Gulf fritillaries are striking orange butterflies, with black spots on the upper wings and iridescent silver on the underside. A tropical and sub-tropical butterfly, it has only existed in the Bay Area since the 1950's.     

Some people use the passion flower as an herbal supplement to assist with anxiety and insomnia, and vitamin supplement companies market passion flower as an aid for stress reduction.  According to the Mayo Clinic, passion flower might help with anxiety, but it can also cause drowsiness, dizziness, and confusion. The flower is used topically, by some, to cure hemorrhoids, burns, and inflammation.

I think I will simply appreciate the plant for its exotically unusual flower, tendency to grow quickly and effortlessly, and for attracting beautiful butterflies into my backyard.