When to plant passionfruit in Australia and New Zealand

When to plant

• Australia: in spring. Gardening Australia says passionfruit are best planted in spring, in free-draining soil in a sunny spot. That gives the vine the whole warm season to establish before winter.
• New Zealand: Tui gives mid-spring to mid-summer, or later where conditions are very favourable.
• Frost: passionfruit is subtropical, and Tui calls for a frost-free climate. Where frosts are light, plant in the warmest, most sheltered spot you have, such as against a sunny wall or fence. Wait until the last frost has passed; the planting calendar shows the frost months for your town.

Where to plant it

• Sun and shelter. Tui recommends full sun, except in very hot areas where part shade is better. It also recommends shelter from wind, next to a wall, trellis or deck.
• Support. The vine climbs by curly tendrils and will cling to almost any support. Give it a strong fence or trellis. Gardening Australia trains the side shoots horizontally along the structure once the main stem reaches the top.
• Room. Space vines at least 2 m apart, as Tui advises.
• Soil. Free-draining, with plenty of compost dug in, because passionfruit are heavy feeders. The compost calculator works out how much to add.

Grafted vines and suckers

Many passionfruit sold for home gardens are grafted: a fruiting variety joined onto a hardier rootstock. The graft is the swollen joint low on the stem. Gardening Australia's instructions are to plant at the depth the vine sat in its pot and not to bury the graft. Otherwise, suckers grow from the rootstock, and they won't be productive.

Which rootstock matters too. The Rare Fruit Club of Western Australia warns that blue passionfruit rootstock (Passiflora caerulea, used for varieties such as Nellie Kelly) is exceedingly invasive, suckers extensively and is hard to get rid of. The club notes that seedling yellow passionfruit is widely used as a rootstock because it is vigorous and resists root and stem rots and nematodes. Whatever the rootstock, cut off any shoot that comes from below the graft or from the ground nearby as soon as you see it.

Feeding, watering and pruning

• Feed for flowers, not leaves. Gardening Australia recommends a complete fertiliser that is not too high in nitrogen. Too much nitrogen gives lots of leaves and not enough flowers. Tui feeds regularly through spring and summer with a fertiliser containing potassium to help flowering and fruiting. The fertiliser calculator turns a label rate into grams for your area.
• Water well in summer. Tui notes that water needs are highest as the fruit approaches maturity. The Rare Fruit Club of WA says water stress may cause young fruit to drop. A drip line under mulch suits a vine well; see drip irrigation.
• Prune in early spring. Tui prunes once the risk of frost has passed, cutting the vine back by about a third to stimulate new growth.

First fruit and how long a vine lasts

Tui puts the first fruit at about 18 months after planting, and each fruit takes two to three months to ripen. Purple passionfruit are ripe when they turn dark purple and fall when the vine is gently shaken. Vines are not long-lived. The Rare Fruit Club of WA gives maximum production of purple passionfruit as only three to four years. Plant a replacement vine a year or two before the old one declines.

Questions