Kiwis make attractive plants, with large, often velvety leaves, furry shoots, clusters of white scented flowers in summer and small egg-shaped fruits, rich in vitamin C. The fruits rarely ripen fully outdoors except in long hot summers, but can simply be picked and ripened indoors.
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Kiwi fruits are attractive, vigorous, twining climbers, usually with heart-shaped furry leaves, creamy-white fragrant flowers in early summer and (on female or self-fertile plants) small hairy or smooth fruits that develop over the summer and into autumn.
There are several factors to bear in mind before buying:
- These are vigorous climbing vines that need plenty of space, large sturdy supports and a warm sunny sheltered site. They can eventually grow to 8m (26ft) or more, depending on the variety
- They require regular maintenance to fruit well – they should be pruned in both summer and winter to keep them in check and encourage successful fruiting
- Plants may take three or four years to start fruiting
- Varieties are either female, male or self-fertile. Most of the widely available varieties are self-fertile, but do check. If you buy a female variety, you will also need a male or a self-fertile variety nearby in order for it to crop. Male plants produce flowers but no fruit. If you only have room for one plant, make sure it’s a self-fertile variety
- Actinidia arguta produces smaller fruits, only about 2.5cm (1in) long, with a smooth skin. Consider growing the self-fertile variety ‘Issai’. The female variety ‘Ken’s Red’ will produce pale red fruits if a male such as ‘Weiki’ or self-fertile ‘Issai’ is growing nearby
- Actinidia deliciosa produces larger fruits, 3–5cm (1¼–2in) long, that are furry skinned, similar to those sold in supermarkets. If you only have space for one plant, choose self-fertile ‘Jenny’, which produces smaller, well-flavoured fruits. Popular female varieties include ‘Hayward’ and Solissimo (‘Renact’), but for successful fruiting with these you will also need a male such as ‘Tormuri’ or self-fertile ‘Jenny’ nearby
- Actinidia arguta is hardier than A. deliciosa, but the young shoots of all are extremely vulnerable to late frost damage and may require protection
What and where to buy
Kiwi plants are available in larger garden centres, fruit nurseries and from online plant retailers. Young plants are sold in a range of pot sizes, depending on their age.
Kiwi fruits are best planted in spring, once the soil and weather are warming up. If planting more than one, space them 3–4.5m (10–15ft) apart.
They require a warm, sheltered, sunny position, preferably against a south- or west-facing wall, although they can be grown in the open in milder areas. Young shoots are extremely vulnerable to frost damage in spring, so avoid planting in a frost-prone site.
Kiwis are vigorous, twining vines and need a large, sturdy support structure, such as a pergola or archway, or strong wires attached to a wall or well-built fence.
It’s best to plant a self-fertile variety, otherwise you need two plants – a female variety and a male or a self-fertile variety – for successful pollination and fruiting.
Water newly planted kiwi fruits during the growing season for at least the first two years.
Established plants will grow and fruit better if watered during dry spells, especially when the fruit is swelling. But the roots are prone to rotting in waterlogging soil, so make sure it drains freely.
Apply a mulch of well-rotted manure or garden compost to the soil in late winter, but leave a gap of at least 5cm (2in) around the base of the stem, to avoid any risk of rotting.
Apply a high potassium fertiliser such as Vitax Q4 or fish, blood and bonemeal when growth starts in spring.
Although kiwi fruits are hardy during winter while dormant, the young shoots are particularly susceptible to frost damage in spring, which can significantly check the plant’s growth. Depending on your local climate, it may be best to protect plants with fleece if they sprout before the last hard frost.
The fruits should also be protected from hard autumn frosts – the safest option is to pick all unripe fruit before the first heavy frost, then ripen them indoors.
Pruning and Training
While kiwi plants can be left to their own devices, they will crop much better if pruned and trained. Unpruned plants will often grow very large, producing leaves and shoots at the expense of fruit.
Flowers and fruit are produced on new shoots that sprout from the base of the previous year’s growth, rather than from older stems. So when pruning, it’s important to retain the oldest part of last year’s shoots, to ensure fruiting.
Kiwis are best grown as tiered espaliers, flat against a wall or fence, with a series of horizontal wires to support the pairs of branches on each side. Pruning aims to stimulate new fruiting growth each year, sprouting from a permanent framework comprising a main central stem and several pairs of horizontal branches.
Alternatively, kiwis can be grown over a pergola or similar sturdy structure, as long as you can access them easily for pruning, in a similar way to espaliers.
Plants should be pruned at planting time, then twice a year, in winter and summer – see below for details.
Initial espalier training
- After planting in late winter or spring, before the onset of new growth, select the strongest shoot and prune it back to 30cm (1ft), cutting just above a healthy bud. Remove the weaker shoots. This will stimulate the development of a strong main stem. Tie this main (leading) shoot to a cane attached vertically to the horizontal wires
- As the main shoot grows, select a pair of side-shoots and train them in opposite directions along each horizontal wire, tying them to it loosely as they grow. Pinch out the tip of these two horizontal shoots (or arms) when they fill the allotted width
- Allow side-shoots (laterals) to develop at 20–30cm (8–12in) intervals along the horizontal arms. Pinch out the tip of these lateral shoots once they have five leaves – these will produce fruiting shoots the following year
- Continue training a pair of shoots to grow along each horizontal wire, spaced at 40–50cm (16–20in) intervals, to develop the main permanent framework of espalier tiers
- In late winter or spring, before new growth starts, prune back the existing lateral shoots (coming off the horizontal arms) to three or four buds beyond the last fruited stems
- Each year, prune back a quarter to a third of the oldest laterals growing from the horizontal arms to a bud about 5cm (2in) from the base. New growth will be produced from this stub in the coming growing season
Start pruning from June onwards. Summer pruning is important to keep these vigorous plants in check:
On shoots where fruit has started to form, pinch back to four or five leaves beyond the maturing fruit
Any non-fruiting laterals can be pruned back to five leaves. Pinch back any regrowth to one leaf beyond the last cut
Kiwis usually start fruiting three or four years after planting. In favourable, warm conditions, especially in southern England, they can produce a prolific crop, especially if plants are well pruned.
They need a very warm, long summer and autumn for the fruits to ripen outdoors. Quite often they won’t ripen fully, but can be picked in autumn and ripened indoors.
Harvest any remaining unripe fruit before the first hard frost and place in a bowl with other fruit to ripen. This can take several weeks. When ripe, they should give slightly when gently squeezed.
Harvested fruit will keep for up to three months in a pierced plastic bag in a fridge.
Kiwi fruits are generally strong, vigorous, healthy plants when grown in suitably warm, sheltered locations. They’re troubled by few pests or diseases, but growth can be affected by the following:
Frost can damage new growth in spring
Drought can cause drooping leaves, brown leaf edges and even complete loss of leaves – keep plants well watered in dry periods
Leaf scorch may show as brown edges to the leaves, caused by drought or drying winds – grow in a sheltered site and water in dry spells
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