The passionate vine!

 

Robin Gale-Baker, from Sustainable Macleod, discusses growing passionfruit. This is one of a series of articles she has written about growing fruit trees (see right hand sidebar). She has also written a number of articles about growing various vegetables, growing various herbs and general growing techniques.

Passionfruit vines are South American in origin and in Australia were originally a tropical plant, grown mostly in Queensland and Northern NSW. Their popularity led to the development of a southern variety known as Nellie Kelly which is ideal for cooler climates like ours.

Passionfruit vines can be finicky to establish and grow but follow the tips here and you will find they are well worth the effort.

My top tips for growing passionfruit:

  • Plant new vines in spring.
  • Plant non-grafted varieties.
  • Build a strong trellis before planting.
  • Plant bee-attracting flowers as an understory.
  • Prune each year.
Selecting a variety

Choose a non-grafted variety. These are much more controllable and do not sucker like grafted varieties.

Choosing the right spot

Passionfruit is self-fertile so one is enough for most gardens as they can spread 6-8 metres both horizontally and vertically.

They require a strong trellising structure which should be built before planting. If planting in a pot, the pot needs to be at least 50cms in diameter, also with a strong support structure.

Passionfruit prefer a warm, sunny, sheltered position, well fertilised soil and regular water. They thrive on nitrogen and iron. In earlier times, offal was placed in the hole before planting to supply these nutrients during the first year. There is no reason these days not to do this but usually blood and bone or pelletised chicken manure is placed in the hole instead.

Spring is the best time to plant a new vine as the warmer soil allows it to establish well before winter. It needs regular deep watering while establishing. The first crop of fruit will appear between 6-18 months depending on conditions and time of planting. In the first year, tendrils will creep across the wires or trellis, firmly attaching the vine to its support. To encourage lateral growth, pick out the small buds.

Pollination is exclusively by bees in the natural world so it is important to plant bee-attracting plants such as lavender, borage, nasturtium and catmint as an understory or nearby. If there is a lack of fruit, hand pollination can be carried out with an artist’s paint brush. Research has shown that bagging the flowers produces less fruit than flowers pollinated by bees. The flowers themselves only last a few days when not pollinated and drop. They can also fall off due to a lack of regular watering. The fruit ripens on the vine, taking 3 -4 months, and drops when ready.

Maintenance

Maintenance of passionfruit vines is essential.

If you have a grafted vine, periodically check for suckers beneath the graft and remove them.

In spring, prune back by about a third. Then fertilise with blood and bone right along the extensive root system and well out from it, not just around the stem. Don’t overdo it though as too much will cause the flowers to drop. A dose of iron chelate several times a year, especially if the vine is yellowing, is necessary too. Potash in spring will strengthen the flowers and as a result produce more fruit. Every 6-8 weeks, spray the foliage with a seaweed extract according to instructions on the bottle. Lightly prune the foliage after fruiting but leave the branches and laterals which are the vine’s framework.

Pests and diseases

Pests of passionfruit include slugs and snails, sap-sucking insects (such as passion vine hopper, scale and mealy bug) and fruit fly.

Slugs and snails eat holes in the foliage. Check with a torch at night and pick them off or use a bait.

Sap-sucking insects suck sap from leaves and stems resulting in flower drop, stunting and leaf yellowing. They all produce honeydew, which attracts ants, and promotes sooty mould. Ants are a sure sign of sap sucking insects. Using a horticultural oil (homemade oil comprises 1 cup vegetable oil to ½ cup detergent, diluted in the ratio of one part oil to 9 parts water and sprayed well on both the top and underside of leaves) is effective but needs to be repeated as it will not kill the eggs.

Sooty mould responds well to a good hosing.

Queensland fruit fly is becoming a serious pest in the northern suburbs of Melbourne. Examine dropped fruit, and fruit on the vine, looking for pinpricks and woody lumps on the skin. Netting (including netting of individual fruit) and Queensland Fruit Fly pheromone (e.g. Wild May) lures are the best ways of dealing with Queensland Fruit Fly, and the immediate disposal of infected fruit is vital. Either burn, or drown infected fruit in a lidded bucket, and definitely do not compost them.

Diseases are few. Fungal diseases including brown spot and septoria (also a problem on tomato plants) and passionfruit woodiness virus are the main culprits. These diseases respond well to pruning as it results in better air circulation, and to spraying with a copper based fungicide such as Bordeaux mix. Passionfruit woodiness virus which produces woody fruit and yellow, crinkly leaves is really a stress disease. If the plant is young, fertilise and water regularly and deeply and it may revive. With older plants, remove and replace with a new vine.

Watering

And finally, watering, my favourite topic! A healthy passionfruit vine needs watering twice weekly, deeply. Watering needs to be comprehensive as the root system will be extensive. Water along the length of the trellis and widely on both sides. People often water only around the main stem and this is a serious mistake. A well-watered vine will be healthy, will avoid flower drop and will produce an excellent crop of delicious passionfruit.

  12 Responses to “The passionate vine!”

  1. My vine is healthy looking with dozens of passionfruit. The fruit is large but the skin is hard and lumpy. Will the fruit ripen and are they edible?

  2. Hi there everybody. I live in Melbourne and have 3 Nelly Kelly varieties. The vine is 2 years old and is full of flowers but the flowers don’t turn into fruit. I really need help.

    • Sam, the most likely problem is a lack of pollinators. Most passionfruit (including Nellie Kelly’s) are self-fertile but still need pollinators to carry the sticky, heavy pollen from flower to flower. In northern climates and western climates in Australia, the best pollinator is the carpenter bee but that one is extinct in Victoria so it is the honey bee or blue banded bee that do the job. Most people reporting this problem find that they need to hand pollinate by picking the male flower and using the anther to transfer the pollen to the stigma of the female flower. I hope this leads to success for you.

  3. Great article thank you.

    We’re in Melbourne and seem to have chosen the perfect position for our vigorously growing and healthy Nelly Kelly.

    Possums (we think) stole our whole crop of fruit last year while they were still green. This year we netted the vine, but may have done so too early as some flowers are dropping now. Can bees get to the flowers if the vine is netted?

    • Hi Joy,

      I think that it all depends on the size of the mesh. If the mesh is mesh size is less than 5mm when stretched, as will soon be required by law, then I think that the answer is ‘no’.

  4. Hi, I suspect my passion fruit has woodiness virus. It’s not a big plant. Can I cut it right down or should I pull it out and start again? If so, can I plant it in same spot as I am limited with sunny spots. Thanks Jill

    • Woodiness virus isn’t necessarily fatal to young vines but vines over 3 years old should be pulled out and replaced (with a non grafted Nellie Kelly). Young vines may come back if watered regularly and fertilised.

      • Hi, I need your help. Our passionfruit is massive but we didn’t prune (because we didn’t know how) and now all off the hundreds of passionfruit have been hit with a fungal disease and gone spotty. It’s currently high summer here in Melbourne so am I able to prune it right back now or do I have to wait? It would be great if you could do a step-by-step video on how to best prune and overgrown passionfruit. Cheers!

  5. Thanks for the advice re growing passionfruit. Do possums eat passionfruit leaves? We have a vine growing over our chook house and, with great regularity, the new growth is being eaten. The vine would be about 5 years old and we are still waiting for it to bear fruit. Any advice would be greatly appreciated. Regards, Ros.

    • Yes, possums do eat and can devour passionfruit leaves.It may be that they are eating the flower buds too. Other reasons for not fruiting are under watering, overwatering when the vine flowers and over fertilising. If you over fertilise you may get plenty of flowers but no fruit. Check to se if you have flowers.

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