Over fertilising your passionfruit vine will result in plenty of lush green foliage but lazy flowers that fall off and do not fruit. We recommend fertilising your Nellie Kelly Passionfruit vine twice a year. Once in early spring after pruning, and again in autumn when fruiting has finished. Be wary of planting your vines too close to septic tanks or compost sites where they may have access to excess ‘food’. Applying rich compost to your vine can also count towards fertilising.
2. A lack of bees
Bees are required to cross-pollinate passionfruit flowers before fruit can form. Planting lavender near your Nellie Kelly will attract bees to your garden and increase your chances of fruit. Unfortunately, in many metropolitan areas urban sprawl has reduced bee activity and increasingly it is the gardener’s job to cross-pollinate.
To play the part of the absent bee, pick a flower from your vine and touch it to the other flowers using a downward swiping motion. This transfers pollen from one flower to the other and is best done at mid-morning.
When a passionfruit vine has lots of foliage but no flowers, insufficient pruning at the start of spring is usually the problem. When a vine is pruned correctly there will be abundant flowers on the new year’s growth. Flowers and fruit will not form on old growth.
Ants in your flowers are no good. Kill them off with an organic insecticide like ‘Pyrethrum’ before they can do any damage.
Yellowing leaves on a passionfruit vine are usually caused by a lack of iron and nitrogen in the soil. A good feed of blood and bone or aged chicken manure will rectify this problem. ‘Winter yellows’ can also be brought on by cold weather, windy conditions or low humidity.
An aphid infestation will cause leaves to curl and can send leaves yellow as the insects suck nutrients from the vine. Spray leaves with an organic insecticide like ‘Pyrethrum’.
The blue passionfruit rootstock used by Nellie Kelly has a much thinner foliage than the black passionfruit, with brilliant blue flowers and soft-skinned, oval fruit that are orange with red pips. If this sounds like your passionfruit vine, then your rootstock has taken over. While the fruit is edible, it has very little pulp and a far tarter taste.
It is essential to remove any growth that appears below the graft, especially in the first 3 months after planting. Use a sharp blade or knife to cut off the growth, as this blinds the offending shoot and prevents any further growth from that site. Never tear or pull the growth off as this will cause multiple shoots to appear.
Sometimes in coarse or sandy ground the fibrous root system of the grafted passionfruit vine will fracture and send up a sucker. Coarse ground can be caused by such things as pets digging around the base of your vine or the neighbour’s renovations disturbing the roots. These suckers may appear many metres away from the base of the vine, often in the middle of your garden bed or lawn. Passionfruit vines planted in pots will also sucker very badly.
As with shoots below the graft, cutting the sucker with a sharp knife will blind this point and prevent further suckers from appearing here again. Never pull or tear the suckers out as this will fracture the root system and cause multiple suckers to grow at this site.
If the suckers are out of control across your garden or the neighbour’s, the best solution is to cut the growth off at ground level and topically apply a weed killer to the cut sites. Be careful when doing this to suckers too close to the original vine (i.e. less than 10cm away) as you run the risk of killing the whole vine.