Passiflora, better known as the passion flower vine or passion fruit, belongs to the family of Passifloraceae. These vines are subtropical or tropical in nature; their foliage will die down to the ground in areas experiencing frosts and freezes. Passion fruits range from being small and egg-shaped to large and oblong, weighing up to eight pounds. The fruit is ripe when it falls from the vine. Passion fruits are high in vitamins C and A.
Passiflora edulis (Purple passion flower)
Passiflora edulis is subtropical in nature and the most cold hardy of the three main species of Passiflora. It grows best in USDA planting zones 5, 6, 7, 8, 9 and 10. The subtropical vines will tolerate 24 hours of frost but will die in freezing temperatures. There are varieties of passiflora edulis hybrids that all have finely toothed 4- to 7-inch trilobed leaves. Vines are aggressive, growing up to 20 feet per year and reaching 150 feet in length. Consider the vine's growth rate when selecting an area to plant.
Springtime brings white flowers with purple centers and purple to purple-black egg-shaped fruits produced in summer. The vine produces fruits after the first year of planting. The Passiflora edulis has the smallest flower of all Passiflora varieties. The fruits are approximately 2 inches long and weigh 1 to 2 ounces, depending on cultivar. The edible section of the fruit is the black seeds encased in orange juice sacs. Passiflora edulis is self-pollinating, and gardeners need only one plant to create fruit. Seeds sowed in a well-draining potting medium, kept moist and situated in a shady area, propagate plants.
Passiflora edulis flavicarpa (Yellow passion flower)
Passiflora edulis flavicarpa is tropical in nature and not tolerant of cold temperatures. Those living in USDA planting zones 9 and 10 will have success growing Passiflora edulis flavicarpa outdoors in the ground. There are several cultivars with finely toothed 4- to 7-inch trilobed leaves. As with other varieties of Passiflora, the vine is quite aggressive, growing up to 20 feet per year and 120 feet at maturity; gardeners should consider this when selecting a planting site.
White flowers with purple centers bloom in spring, and yellow fruits approximately 3 inches in diameter and weighing 2 to 3 ounces form in summer. Vines produce fruits after the first year of planting. The black seeds encased in juicy orange sacs are edible. Passiflora edulis flavicarpa requires a pollinator from another plant not taken from the parent in order to produce fruit. To ensure fruit, gardeners should plant at least two Passiflora edulis flavicarpa vines so the flowers will pollinate each other through bees and other insects. Seeds sowed in a well-draining potting medium, kept moist and situated in a shady area, propagate plants.
Passiflora quadrangularis (Giant Granadilla)
Passiflora quadrangularis is the "big boy" of the Passifloras, producing the largest fruits. The vine is tropical in nature and is not cold tolerant. It is suitable for growing in USDA planting zones 9 and 10. The leaves are 4 to 8 inches long and oblong shaped. This too is an aggressive grower, growing up to 150 feet at maturity and approximately 20 feet per year.
Passiflora quadrangularis flowers have maroon centers and bloom in spring. The flowers droop, resembling a lampshade. Round or oblong 4- to 8-inch fruits form in summer and weigh 8 to 11 pounds. Vines produce fruits after the first year of planting. Unlike other varieties, the rind of the Passiflora quadrangularis is edible as well as the seedy juice sacs. Pollination is required for the setting of fruit and is accomplished by hand-dusting one flower from the plant with another flower from the same plant.