Although not a tropical native, the passion flower vine easily creates a jungle atmosphere with its exotic blooms and lush foliage. In USDA zones 6 to 9, Passiflora incarnata will survive outdoor winters and return in May as long as it is well-mulched and the ground doesn't freeze. In locations where winter months are brutal, dig up passion flowers and bring them inside. This plant is easy to care for indoors or out, so don't be intimidated by the thought of bringing it in to ride out the winter.
Prune any dead or damaged wood from your passion flower plant in early fall, but well before the first expected frost for your area. Look through the plant's foliage. Remove any stem that's broken, or dead and brown. Make a clean cut with sharp shears right at the point where it grows from a larger limb, and don't leave a stub.
Dig up and plant the passion flower in a clay pot that's 2 inches larger in diameter than the rootball and as deep as the soil level it occupied in the garden. Clay is best because it facilitates maximum drainage and can compensate for over-watering errors. Fill the pot with the soil the plant is currently growing in.
Test and adjust the soil's pH as needed. Passion flowers prefer a range of 6.5 to 7.5. Do this twice a year. The pH level can be lowered with sulfur or raised with lime, and follow the manufacturer's instructions dosage.
Place the potted passion flower in the brightest spot in the home but out of direct sun. It will benefit greatly from good air circulation. Preferred daytime temperatures are 55 to 65 degrees F., with slightly cooler temps at night being tolerated.
Water occasionally, just enough to evenly moisten the soil surface. Allow the surface to dry out just slightly before watering again. Frequency will vary according to the temperature and humidity conditions . A good indication that the plant is ready for more water is if the soil surface feels dry to the touch.
Set the passion flower plant outside when the weather permits throughout the winter months. If temperatures rise above 50 degrees F., a daytrip to the great outdoors will do the potted plant a world of good. Make sure it isn't exposed to direct sunlight.
Plant the passion flower back outside after all danger of frost has passed and sustained temperatures remain above 50 degrees F.