The passion flower vine (Passiflora) is native from southern Brazil, throughout Paraguay, and in parts of northern Argentina. Before 1900, the passion vine was naturalized and flourishing along the coast of Australia. Seeds of the passion fruit were brought from Australia to Hawaii in 1880. There are dozens of different varieties of passion vine, both edible and non-edible varieties. Tea, juice and herb capsules are a few of the products made from the plant and its fruit.
Passion Flowers attract many species of butterflies such as the Great Spangled Fritillary, Zebra Longwing, Variegated Fritillary, Julia Heliconian, Checkered White, Cloudless Sulphur, Gray Hairstreak, Gulf Fritillary, and others.
Passifloras prefer a frost-free climate. Some cultivars can take temperatures into the upper 20o F without serious damage. The Blue Passion Vine is relatively cold-hardy and salt tolerant but does not grow well in extreme summer heat. The yellow passion fruit is tropical and sensitive to frost. The purple and yellow forms both need protection from the wind. The vast majority of Passifloras are found in Mexico, Central and South America although there are additional representatives in the United States, Southeast Asia, and Oceania.
Many species of passion flowers bear edible fruits. Among these are Passiflora alata, P. antioquiensis, P. edula, P. incarnata (the Maypop of the southern United States), P. laurifolia, P. ligularis, and P. maliformis.
Passiflora vines require full sun except during very hot summer days when they should have partial shade. The vine is a fast grower and can easily get out of hand. If possible, plant it next to a chain link fence or on a trellis. These vines will grow in many types of soil, but make sure the plant has excellent drainage. Also, passion vines grow best in soils with pH levels of 6.5-7.5. If you want to keep the vines flowering almost continuously, regular watering is necessary. The vines are shallow-rooted and will benefit from a thick layer of organic mulch on the soil.
Although the vines don’t need pruning to encourage growth, prune this fast-growing vine to keep it under control. Prune in early spring when new growth appears. Avoid cutting the main stems. Remove any unwanted twining stems. Passiflora vines are vigorous growers and require regular fertilizing. Don't use 20-20-20 liquid fertilizer since this may promote heavy vine and leaf growth at the expense of more flowers. Use an organic fertilizer with a ratio of 2-1-3. All fertilizer labels have three bold numbers. The first number is the amount of nitrogen (N), the second number is the amount of phosphate (P2O5) and the third number is the amount of potash (K2O). These three numbers represent the primary nutrients nitrogen(N), phosphorus(P), and potassium(K).
Passion flower was formerly approved as an over-the-counter sedative and sleep aid in the U.S. but was taken off the market in 1978 because its safety and effectiveness had not been proven. However, it may still be sold alone or in combination with other herbal products.
Steps to success with Passifloras:
1. Find a location where the soil drains well. If there are still water puddles 5-6 hours after a rain or after watering, choose another spot. These plants will not survive in soggy soil.
2. Plant your passion flower vine where it will receive a full day of sun or partial light shade. More sunlight tends to produce more flowers. Check the winter hardiness information provided for each variety. If you've chosen a cultivar that's marginally hardy in your part of the country, plant it near a sunny wall to provide extra insurance against winter cold. Shelter your plant from strong or drying winds.
3. Dig a hole and situate the vine so the soil on the pot's root ball is level with the soil in your garden bed. Tuck the plant in and tamp down the soil to remove any air pockets.
4. After planting, water well, gently soaking the soil and settling it around the plants. Plants will develop sprouts quickly in warm soil. If the soil is still quite cool, wait until it warms before planting outdoors.
5. Water as needed during the growing season. Passion flower vines require an average amount of water, about 1–1.5 inches a week.
6. Water lightly through the fall in cold areas and sparingly during the first winter in warm areas if your climate is dry. Your vine will rest for a few months before beginning its next growing cycle in the spring.
(Photos, top to bottom: By Bernard Loison (http://www.mytho-fleurs.com/) [CC BY-SA 2.5 (https://creativecommons.org/licenses/by-sa/2.5)], via Wikimedia Commons; By Art Poskanzer from Berkeley, USA (passion vine Uploaded by uleli) [CC BY 2.0 (https://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons; By Wilrob [GFDL (http://www.gnu.org/copyleft/fdl.html), CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/) or CC BY-SA 2.5 (https://creativecommons.org/licenses/by-sa/2.5)], from Wikimedia Commons; By John Ocampo [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)], from Wikimedia Commons; By Wilrob [GFDL (http://www.gnu.org/copyleft/fdl.html), CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/) or CC BY-SA 2.5 (https://creativecommons.org/licenses/by-sa/2.5)], from Wikimedia Commons)