Most of the Passifloras, or passion flower plants, thrive well in USDA Plant Hardiness Zones 5 through 9. Many lose their leaves during the winter, but the vines happily resume rampant growth each spring. To keep your passion vine healthy, vigorous and manageable, prune it each spring. It's safe and desirable to begin pruning your passion flower plant after its second year. This will open it up and allow for maximum air circulation as well prevent the excessive accumulation of dead wood.
Use clean, sharp shears to prune your passion flower vine early in the spring after new growth has begun. Remove any dead, damaged or diseased material. Cut each stem all the way back to the point it's growing from.
Cut back excessively long or shaggy vining stems that you find unattractive.
Prune frost- or winter-damaged stems back to 1 to 2 feet tall. Make your cuts just above a bud or side shoot if possible. This will encourage the plant to produce copious new growth, which will bloom for you in a year or two.
Cut all stems of older or excessively overgrown passion plants back to about 8 to 12 inches tall. It's an excellent way to rejuvenate and invigorate them. This will also encourage thin or leggy plants to produce fuller growth.