Black passion fruit is widely adapted but requires a rich, well-drained soil and support — in the form of a trellis, pergola, or fence, ideally about two metres high. Passion fruit requires full sun to fruit reliably, although it tolerates occasional mild frosts.
How many to grow?
The flowers are self-pollinating and one vine will supply most families. Vines start bearing within 12 months of planting. Black passion fruits flower in spring to produce a summer crop, then flower again in autumn for a winter crop.
The most common species are black, or purple passion fruit — Passiflora edulis, yellow passionfruit — Pedulis flavicarpa and banana passion fruit — P mollissima. Other species that are widely grown in subtropical to tropical regions are: The Jamaican honeysuckle or water lemon — P laurifolia, the sweet granadilla P ligularis, generally thought the finest passion fruit of all with purple and white flowers and large orange fruits filled with sweet and fragrant pulp; the giant granadilla — P quadrangularis with crimson flowers and melon-sized fruits that have fragrant sweet pink pulp; and the sweet calabash — P maliformis which closely resembles the sweet granadilla and has grape-flavoured pulp amongst other.
Dig generous amounts of compost — and dolomite if soil is acidic — into the soil before planting in spring. Mulch the plant well, but keep it away from the stem, and water in thoroughly. Help young vines to climb up their support by attaching with soft ties. Fertilise in spring, early and late summer, and mid-autumn with extra compost or a pelleted slow-release organic fertiliser. Also water regularly. Prune in spring every second year, progressively remove any branches below 60 cm to improve air circulation, and also thin out old branches. Different passion fruits are usually grafted onto yellow passion fruit rootstock, which is resistant to various root rots.
Pests and diseases
Root rots occur on ungrafted plants. Common problems are a leaf-spotting fungus and a virus that makes fruit ‘corky’.
Harvesting and storing
Harvest black passion fruit when fully sized and coloured — they are at their best when slightly wrinkled. The Panama varieties, however, are ripe when still smooth. The pulp can be extracted and frozen.