Pumpkins & granadillas to grow and enjoy
Plant a fast-growing passion fruit vine in autumn or spring and enjoy a home-grown tropical feast (and lots of shade) in summer.
Is there a better place to spend a lazy late-summer afternoon than in the shade of a granadilla vine? Under this cool canopy of shiny green leaves, aromatic purple balls and, if you’re lucky, the very last intricate purple-and-white flowers of the season, one can simply reach out for a somewhat shrivelled passion bomb to add some tropical punch to your drink. Frankly, you could simply pick one off the ground, because granadillas drop when they’re ripe.
Purple Passifloraedulis and yellow Passifloraligularis, also known as tropical passion fruit, are both native to South America but are now grown all over the world – even indoors or in heated tunnels in colder climates. The fruit not only offers endless possibilities in the kitchen but is also an excellent source of fibre and vitamin C, has antioxidant properties and contains polyphenols that could help prevent cardiovascular disease.
1 Choose the right spot
The average lifespan of a granadilla is about seven years, but for commercial purposes farmers plan on three years because the productivity of the vine decreases after that.
• SUN & WIND Granadillas are subtropical plants but prefer moderate temperatures throughout the year. A monthly average of no more than 30°C is perfect, and temperatures should preferably never drop below 5°C. Severe frost is a complete no-no. A good tip is to plant granadillas on the cool side of your house if you live in a really hot area and on the warm side in a cooler area. Choose a relatively sheltered position, as the plants need protection from strong winds.
Here at Platteland we’ve seen how a combination of heat wave and hot berg wind can kill a well-established granadilla vine in one day.
• SOIL The granadilla has a deep but surprisingly small root system (considering the size of the plant it has to sustain), so deep, fertile soil with excellent drainage, lots of compost and a thick mulch layer are crucial. If you have clayey soil, the plant might develop a shallow root system, and excessively wet soil can lead to root rot and other diseases.
Prepare the soil properly: dig a generous hole of 1m x 1m x 1m, and add lime and phosphates along with wellrotted manure and compost to the soil.
• A PLACE TO CLIMB Thanks to rather determined tendrils, a granadilla will climb up and over almost anything and can indeed smother other plants. Make harvesting time easier by planting a granadilla far from other plants. Make sure you have a sturdy trellis about 2m high in place to support the mature plant when it is heavy with fruit. Use termite-resistant wood.
Train the lead shoot loosely up your trellis and remove the side shoots (not the leaves) in the early stages.
Vines tend to look sad and bare during winter, so it’s a good idea to plant an evergreen creeper such as evergreen clematis, star jasmine ( Trachelospermum jasminoides) or Jasminium angulare and train it up the same trellis.
2 How to plant
The easiest way to a home-grown granadilla harvest is to buy seedlings at a nursery. Transplant them now or in late August or September, when the really cold nights have passed. Prepare the soil well and allow for about 2m between plants.
Granadillas can be grown from seed and can usually be transplated about three to six months after sowing. Just keep in mind that the seeds of many of the hybrid varieties of shop-bought fruit won’t grow true to type.
To obtain seeds, use ripe, healthy fruit, scoop out the contents and wash thoroughly to separate the seeds from the pulp. Let the seeds dry in the shade for at least two days before sowing in deep seed trays or plant bags filled with sterilised soil.
Many gardeners believe, however, that germination is enhanced if the seeds, along with the pulp, are left to ferment in a container for about three days before washing and drying the seeds and sowing them as soon as possible.
Fresh seed will take 10 to 20 days to germinate. Push a thin stake into the soil next to each seedling to train the plant up the stake, and regularly remove side shoots. The seedlings can be transplanted when they are 30cm to 40cm high.
3 Keep them happy
• WATER Like all tropical plants, granadillas like humidity and need a well-distributed average rainfall of about 1 200mm per year. If you live in a much drier area you’ll have to supplement it with regular irrigation. In particular, the plants need a lot of water while fruit are being formed, but make sure the site is free-draining.
Do not overwater – this could lead to root problems. >
• FEEDING Compost and a sprinkling of organic slow-release fertiliser twice a year should be more than enough if the soil was properly prepared. Avoid overfeeding – too much nitrogen will lead to a mass of soft green leaves (which insects find irresistible) and very few fruit.
• PRUNING Severe pruning can lower production – most vines really only need to be pruned when they become unproductive, to stimulate new growth and to let in more light and air. The best time for pruning is from July to August. Start by removing dead, old or diseased parts, then snip off any shoots growing along the ground. Keep your instruments – and your hands and gloves – clean and diseasefree by rinsing them in water with 10% bleach added to it.
• PESTS & PROBLEMS Common pests are stink bugs and tip wilters. The best way to control them is to pick them off by hand – rather laborious but effective. Also look out for the disease foot rot ( dikvoet), which doesn’t seem like a disease at all but manifests at the base of the stem. The stem thickens and cracks at the surface of the soil. This allows organisms into the stem, causing it to rot. Overwatering and water logging increases the chance of foot rot.
4 It’s harvest time!
In ideal conditions, your first harvest should be ready within six to nine months after transplanting the seedlings. The plants reach their full bearing potential at about 18 months and will usually deliver a main crop any time from November to midMarch, and a smaller crop in June and July. In Mpumalanga, a third crop is sometimes enjoyed from March to May.
You don’t really have to worry about picking the fruit because the ripe ones will drop to the ground – collect them as soon as possible and keep them in the refrigerator. If you do decide to pick them yourself, stick to those with a deep-purple colour. With granadillas, a wrinkled skin usually is a good sign, but don’t keep them for too long or they will simply dry out.
Granadillas are associated with a host of health benefits thanks to high concentrations of vitamins and minerals. The fruit are ready to eat from six to nine months after planting, and drop to the ground when they’re ripe.
1 Only a sturdy trellis would support a full-grown granadilla vine heavy with fruit. 2 The flower of
Passiflora edulis is hard to beat when it comes to exotic looks in the kitchen garden. 3 It might seem delicate, but a granadilla tendril is remarkably strong. 4 Granadilla plants reach their full bearing potential at about 18 months.