Take the worry out of growing this popular backyard crop with these tips. Remember passionfruit are subtropical plants so, although they’ll grow in most parts of Australia, in cooler areas they need a warm, sunny, sheltered spot with fertile soil and regular water to thrive. Plant a passionfruit vine between spring to early autumn and provide it with a wall or framework to climb on.
1. Age before beauty
Passionfruit vines don’t flower and fruit straightaway. In the subtropics they may begin fruiting in six to 12 months from planting, but in most parts of temperate Australia it takes 18 months before flowering begins and fruit forms.
2. Feed and water that growth
Keep these hungry vines weed free, well watered (especially when there’s little rain) and fed from spring to autumn. Use pelletised flower and fruit, a citrus food or a chicken poo fertiliser. Water plants well before adding fertiliser then spread it around the base of the stem and along the area where the roots are growing. After feeding in spring, spread organic mulch such as compost or aged cow manure 2 to 3 centimetres deep. Don’t let it build up against the stem and don’t dig it in as this may encourage suckering.
3. Avoid suckers
Many passionfruit are grafted plants. From time to time the understock (the root system your vine is grafted on to) starts to grow. It can out grow the productive vine and become weedy. Always remove suckers from below the graft area and avoid damaging the root system as this can encourage suckering.
Passionfruit vines don’t need pruning to encourage fruiting, but they may need it to remove overgrown growth or keep the vine under control. The best time to prune is in spring as new growth resumes. Avoid removing main stems, just cut back unwanted twining stems.
5. Flowers but no fruit
If the vine is established and well cared for it should begin flowering in spring and continue into autumn. All being well these flowers are quickly followed by green fruit, which gradually ripens to black or purple in the case of ‘Nellie Kelly’ or golden brown or red in the case of other varieties such as ‘Panama Gold’. If there are flowers but no fruit, try hand pollinating the blooms using a small dry paintbrush or a cotton bud to transfer pollen from stamens to the stigma. Repeat this regularly until you see fruit forming. You can also try planting flowering annuals or herbs around the area to entice pollinators into your garden.
Rain, overcast conditions, cold and wind can all delay fruit formation. Over fertilising with a high nitrogen fertiliser can cause flowers to drop and prevent fruit from forming.
6. No flowers
If you've planted the vine in the correct position and you're still not getting flowers once established it's likely not getting the nutrients it needs. Try feeding in September after pruning and again in autumn with a liquid plant food such as Amgrow Organix Harvest or Yates Thrive Concentrate Flower and Fruit.
Some passionfruit varieties require another vine to provide cross-pollination and produce fruit however the commonly grown ‘Nellie Kelly’ and ‘Panama Gold Select’ are self-fertile.
Passionfruit vine hopper, also known as fluffy bum due to the appearance of its young, can attack vines and may lead to fruit or flower drop. These can be squashed or hosed off. Juvenile fluffy bums can be treated with a garden spray such as a pyrethrum-based insecticide (apply according to label instructions). Vines may also be attacked by scale. Use a horticultural spray oil to deal with scale.
9. Is it ripe?
Fruit colour at ripening can be variable and some ripe fruit may not be highly coloured. If green fruit drops to the ground it is always worth tasting it to see if it is ripe. Fruit that’s fallen but has no pulp has not being properly fertilised. Ripe fruit left on the ground may get sun burnt so regularly collect fruit. Also keep the ground around your passionfruit clear of weeds or long grass so it’s easier to find fallen fruit.