Passion Fruit (Yellow, Layer) Plant

The passionfruit vine is a shallow-rooted, woody, perennial, climbing by means of tendrils. The alternate, evergreen leaves, deeply 3-lobed when mature, are finely toothed, 3 to 8 in (7.5-20 cm) long, deep-green and glossy above, paler and dull beneath, and, like the young stems and tendrils, tinged with red or purple, especially in the yellow form. A single, fragrant flower, 2 to 3 in (5-7.5 cm) wide, is borne at each node on the new growth. The bloom, clasped by 3 large, green, leaflike bracts, consists of 5 greenish-white sepals, 5 white petals, a fringelike corona of straight, white-tipped rays, rich purple at the base, also 5 stamens with large anthers, the ovary, and triple-branched style forming a prominent central structure. The flower of the yellow is the showier, with more intense color. The nearly round or ovoid fruit, 1 1/2 to 3 in (4-7.5 cm) wide, has a tough rind, smooth, waxy, ranging in hue from dark-purple with faint, fine white specks, to light-yellow or pumpkin-color. It is 1/8 in (3 mm) thick, adhering to a 1/4 in (6 mm) layer of white pith. Within is a cavity more or less filled with an aromatic mass of double-walled, membranous sacs filled with orange-colored, pulpy juice and as many as 250 small, hard, dark-brown or black, pitted seeds. The flavor is appealing, musky, guava-like, subacid to acid.

Propagation
Passion fruit vines are usually grown from seeds. With the yellow form, seedling variation provides cross-pollination and helps overcome the problem of self-sterility. Some say that the fruits should be stored for a week or two to allow them to shrivel and become perfectly ripe before seeds are extracted. If planted soon after removal from the fruit, seeds will germinate in 2 to 3 weeks. Cleaned and stored seeds have a lower and slower rate of germination. Sprouting may be hastened by allowing the pulp to ferment for a few days before separating the seeds, or by chipping the seeds or rubbing them with fine sandpaper. Soaking, often recommended, has not proved helpful. Seeds are planted 1/2 in (1.25 cm) deep in beds, and seedlings may be transplanted when 10 in (25 cm) high. If taller–up to 3 ft (.9 in)–the tops should be cut back and the plants heavily watered.

Some growers prefer layers or cuttings of matured wood with 3 to 4 nodes. Cuttings should be well rooted and ready for setting out in 90 days. Rooting may be hastened by hormone treatment. Grafting is an important means of perpetuating hybrids and reducing nematode damage and diseases by utilizing the resistant yellow passionfruit rootstock. If seeds are available in the early spring, seedlings for rootstocks can be raised 4 in (10 cm) apart in rows 24 in (60 cm) apart and the grafted plants will be ready to set out in late summer. If seeds cannot be obtained until late summer, the seedlings are raised and grafted in pots and set out in the spring. Scions from healthy young vines are preferred to those from mature plants. The diameter of the selected scion should match that of the rootstock. Either a cleft graft, whip graft, or side-wedge graft may be made.

Seasons and Harvesting
The different flowering seasons of the purple and yellow passionfruits have been mentioned under “Pollination”. In some areas, as in India, the vines bear throughout the year but peak periods are, first, August to December, and, second, March to May. At the latter time, the fruits are somewhat smaller, with less juice. In Hawaii, passionfruits mature from June through January, with the heaviest crops in July and August and October and November. With variations according to cultivar, and with commercial cultivation both above and below the Equator, there need never be a shortage of raw material for processing.

Ripe fruits fall to the ground and will roll in between mounded rows. They do not attract flies or ants but should be collected daily to avoid spoilage from soil organisms. In South Africa, they are subject to sunburn damage on the ground and, for that reason, are picked from the vines 2 or 3 times a week in the summertime before they are fully ripe, that is when they are light-purple. At this stage, they will reach the fresh fruit market before they wrinkle. In winter, only one picking per week is necessary. For juice processing, the fruit is allowed to attain a deep-purple color. In India and Israel, the fruits are always picked from the vine rather than being allowed to fall. It has been found that fallen fruits are lower insoluble solids, sugar content, acidity, and ascorbic acid content.

The fruits should be collected in lugs or boxes, not in bags which will cause “sweating”. If not sent immediately to processing plants, the fruits should be spread out on wire racks where there will be good air circulation.