Passionfruit are a popular garden plant as their scrambling habit is put to good use to hide unsightly fences and walls. Only three of the three hundred or so species are grown for their fruit, the Purple Passionfruit (Passiflora edulis), the Golden Passionfruit (P. flavicarpa) and the Banana Passionfruit (P. mollissima).
Passionfruit are sub-tropical in origin, but will grow in protected locations in cooler areas. They cannot abide wind or frost. Well-drained soil is essential and they are heavy feeders. Copious quantities of mulch and compost are a requirement. Where the soil has a lot of calcium, manganese deficiency will need to be remedied by incorporating seaweed in the mulch, or foliar sprays of Seasol or Maxicrop.
Passionfruit are generally propagated from seed. Extract the pulp and ferment it for three days at 21° C. The seeds should come from a disease-free plant.
Being a vine, some sort of trellis is necessary to support the plants. Commercially, a two wire T trellis is used. The wires are 50 cm apart and 2 m above the ground. The rows are 3 m apart with the vines 4-6 m apart in the row.
The vines are planted in spring when all danger of frost is past. They must be well watered in. The leading shoot is trained by tying it to a stake until it has reached the trellis. Side shoots are removed to encourage this happening as soon as possible. When it does, its tip is pinched off and two side shoots tied to the parallel wire. The home gardener will probably have three wires along the fence at heights of 1, 1.5 and 2 m.
Passionfruit produces flowers and fruits on the current season's growth. If these are not pruned away, the centre of the vine becomes a tangled mess. In cooler areas, prune back all laterals to 30 cm in spring. In the tropics, prune passionfruit in winter. Summer pruning helps the fruit to colour and allows any necessary spraying to be more effective.
Passionfruit are self fertile, but fruit set can be erratic, particularly on young vines. Rain severely reduces the amount of fruit. Spring pruning encourages some late flowers, extending the flowering and consequently fruiting period.
Passionfruit ripen in the summer, though there is a smaller autumn crop in the tropics. Pick the fruit as soon as they develop their purple colour, before they drop. To avoid the skin shrivelling, pick in the morning and store them in a plastic bag. The pulp can be deep frozen for later use. Yields vary and you can expect 15-30 kg of fruit per year from a mature vine.
A variety of fatal diseases make commercial growing a dicey proposition. The lifespan of a vine rarely exceeds six years. Many of these are viruses, so good control of the aphids responsible for their transmission is essential.
Sprays of soap, garlic, or pyrethrum can control scale insects. Fungal diseases can be controlled by half strength Bordeaux or other copper based fungicide. Thinning the foliage allows better air circulation, reducing the chance of fungal disease, and better coverage with sprays.
Kiwi Fruit, or Chinese Gooseberry
Hardly known in its native China, this fruit was adopted by New Zealand, renamed and popularised through most of the world. It is adapted to a mild climate, free from severe frosts that affect the fruit and new growth. They need good protection from wind and have a low chilling requirement.
The soil must be reasonably well drained and have good moisture reserves. The vines have very shallow roots, so mulching heavily ensures this. They are heavy feeders, so copious quantities of compost are needed to assure a good supply of fruit. On alkaline soils, iron deficiency can be a problem.
Male and female Kiwi Fruit flowers are on separate plants. The usual number of females per male plant is nine. For the home gardener, female plants grafted with a male lateral are available. There is a risk in this, in that the male part can be accidentally removed during pruning. Clearly identifying the lateral with a coloured plastic ribbon will help to avoid this unfortunate occurrence.
Kiwi Fruit are propagated by grafting the desired varieties onto seedling rootstock. The seedlings should be about the thickness of a pencil and the technique used is generally whip and tongue grafting. Shoots arising from the rootstock must be removed as they develop. The standard commercial female variety is Hayward and the male Tomuri. Other varieties available include: Bruno, large fruit, but poor keeping. Matua is its pollinator.
Monty, prolific bearer requiring fruit thinning. Tomuri is its pollinator.
Abbot, earliest flowering and medium sized fruit. Matua is its pollinator.
The best trellis for Kiwi Fruit is a T with 3 wires 1.8 m high and the wires on a 1.2 metre cross piece. The trellis must be very strong as the fruit and vines weigh a considerable amount. The newly planted vine is trained to the wire by rubbing off any lower shoots and then training the two topmost shoots along the centre wire. Tying these is better than twisting them around the wire, which tends to strangle the shoots. Lateral shoots from these arms are left at 30-40 cm intervals and are pruned back to to two or three buds each winter. The laterals should be renewed every three years to ensure continuing fruitfulness. Summer pruning consists of removing all but three buds past the last fruit. Male plants are pruned hard after fruit set.
The first crop will be harvested when the vines are five years old. Maximum production is attained in eight years. Fruit matures in autumn and winter. Pick the largest fruit first, leaving the smaller fruit to increase in size. The fruit ripens off the vine in a few days at room temperature. Placing the fruit in a paper bag with a ripe apple or banana accelerates the process of ripening.
The main pests of Kiwi Fruit are Greedy Scale and Light Brown Apple Moth. Greedy Scale can be controlled by soap, garlic, onion, or pyrethrum sprays. LBAM is best controlled by Bacillus Thuringiensis (Dipel).