Plant Doctor Archive

Problematic passionfruit

LAST year a self-seeded passionfruit came up in my vegetable garden. I trained it along a trellis and it grew well, flowered and set fruit. Some of the fruit developed round marks and some nearby leaves fell off, but leaves and fruit further along the same stems were not affected. Was this a deficiency in the soil? If so, why didn't it affect all the fruit and how should I prune the vine?

IT sounds as if your vine has been affected by one of the leaf spot diseases that passionfruit can suffer from. They tend to be worse in wet, cool conditions, so it sounds like the infection didn't spread to the rest of the plant once the weather improved. To avoid the same problem in the future, you could give the vine an occasional spray with a copper-based fungicide, such as Super Copper, especially during cool, wet conditions.

Often, they don't need much pruning apart from thinning out a few shoots if growth is excessively dense, to open up the centre of the vine to the light or to cut back very long shoots. Don't cut them hard back overall. You can prune after all the fruit is finished or in early spring.

Passionfruit vines need lots of nutrients to encourage fresh new growth and lots of fruit, so a fertile vegetable garden is an ideal place for one. They are relatively shortlived, however, and after four years or so may lose vigour and need replacing.

Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.