This group of fruits is native to South America and although there are many members in this family the most popular in New Zealand is the black passion fruit or Passiflora edulis. In Northland we are luckily enough to be able to plant them all year round.
Planting Passionfruit are a subtropical fruit that needs the sunniest warmest place in the garden. Free draining soil is essential, heavy wet soils like clay are not suitable, if the roots become waterlogged, root rot will set in and the vine will fail. Frost protection needs to be considered, while an established vine will stand a few degrees of frost, young plants won’t. When choosing your site consider a wall or fence this will not only give it support, protection from the wind but the added benefit of some reflected heat.
Fruit is usually produced about 15 months to 2 years from planting and from then on will produce fruit from February through to September. The vines don’t last forever though reaching their peak production around 5 years. After this they will start to decline, be prepared for this and have a replacement on the go at about the round about the third year mark of your first vine.
Passionfruit vine are heavy croppers, because of this they need a lot of food, prepare the soil by digging in plenty of compost and add a good couple of handfuls of blood and bone around the root zone.
Care During the year additional fertilise is necessary, it is no exaggeration that they need plenty of food and so don’t be mean. Use a prepared citrus fertiliser; apply in August and again in midsummer.
Watering the vines during the drier months is important; fruit will often shrivel on the vine from lack of water. Use mulch to help this will also add more nutrients to the soil as it rots and suppress weeds. Make sure you don’t apply the mulch against the vine stem as this will as it will cause the bark to rot.
Training and Pruning Not everyone prunes but it will benefit the production, as fruit is only borne on new season growth. Without pruning the vine can become a dense tangled mass of shoots many of which are non-fruiting and become a place to harbour pest and diseases. Pruning is after harvest and consists of first removing, any dead, diseased or spindly growth. Then the main laterals are cut back by a third, this will encourage the growth of new shoots. To train, choose 4-5 strong laterals these are the main stems that the secondary fruiting arms will come off of, these main laterals are trained up through the trellis or support wires.
Pest and Diseases Passionfruit are susceptible to a few pests and diseases but more often than not it is poor drainage and lack of food that will be the main cause of vine failure. Like all plants the best defense against pests and diseases is a healthy plant.
To spray against Brown spot, mealy bug and passion vine hopper use Copper Oxychloride and alternate with Pyrethrum, Spray every 4-6 weeks. Pyrethrum spray has a low withholding period and needs to touch the bug to kill it, so make sure you spray the undersides of the leaves. It is harmful to bees so use in the evening when they have gone home.