Out of over 500 species in the Passifloraceae family, Passiflora edulis is the only member to bear the designation "passionfruit." The fruit grows on a perennial vine with tendrils that help it cling when it climbs. Purple passionfruit vines will flower in early spring, while the yellow blooms later in spring until fall. Passionfruit vines are hardy to USDA zones 9a to 11.
Choose an area to plant your passionfruit vine that is sunny and protected from winds. It should also be next to a fence, wall or pergola on which it can climb.
Deliver a soil sample to the county cooperative extension office for pH testing. Passionfruit vines require a soil pH of 6.5 to 7.5. The agent will also give you suggestions as to appropriate soil amendments to add to correct the pH of your soil.
Amend the soil by adding a 3-inch layer of compost, a 2-inch layer of sand and the recommended amendments to the planting area and mixing them with the existing soil to a depth of 8 inches.
Plant the passionfruit seed 1/2 inch deep, and cover with soil. Water the area carefully to avoid disturbing the seed and keep the soil moist but not soggy. The seed should germinate within three weeks.
Fertilize the passionfruit vine for the first time when it reaches 10 inches tall. Use a 10-5-20 fertilizer, diluted to half strength and poured onto the soil around the plant. When the vine matures, supply 3 pounds of the fertilizer three times per year.
Lay down a 2-inch layer of mulch at the base of the vine and spread it out in all directions to 5 inches.
Water to keep the soil moist at all times. Especially during fruit growth, the passionfruit vine needs to be kept moist.
Prune passionfruit vines right after harvest by removing weak wood. Cut back the entire vine by one-third.