Actinidia, kiwi tree: planting, pruning, harvesting

Description and botany

Kiwi (Actinidia chinensis or deliciosa), also called kiwifruit vine, Chinese gooseberry, or even “plant mouse”, is a climbing fruit bush belonging to the Actinidiaceae family, like its cousin the Kiwai or Siberian kiwi (Actinidia arguta) which produces smooth-skinned fruit.

Kiwi is native to temperate regions of China, not New Zealand, which nevertheless remains its main exporting country. Kiwi arrived in France, in Nice, in 1904 and has since become widely acclimatised, mainly in the Landes, the Midi and Corsica.

Around 30 Actinidia species are recognised but only five produce edible fruit and are cultivated for that purpose in France. Among them, Actinidia deliciosa whose fruits have a villous skin and its many cultivars, some self-fertile such as ‘Jenny’ or ‘Solo’, the best known. Actinidia chinensis produces smooth-skinned kiwis, while Actinidia arguta, also called “Kiwai”, bears fruits smaller than traditional kiwis that can be eaten with the skin on.

This vigorous, woody, sarment-bearing liana-bush clings to any support thanks to its tendrils. Its long sinuous, voluble stems can grow by 3 m a year to reach 6 m in height, sometimes more in favourable conditions, with a spread of about 4 m at maturity. Young shoots with reddish bark are covered with a reddish down. Kiwi demonstrates notable longevity and can live between 50 and 100 years.

Actinidia foliage is also of interest. Shoots bear large, broad, deciduous, alternate leaves of 8 to 20 cm. Ovate or heart-shaped, they are entire, with prominent veins that are paler and dentate margins ending in bristles. Medium to dark green above and paler beneath, most leaves are villous and covered with a fine down. Actinidia kolomikta, the Arctic kiwi, is an ornamental species distinguished by truly decorative leaves, tricoloured, green variegated with pink and white on their lower half.

Multiple foliage types: Actinidia deliciosa and Actinidia kolomikta (ornamental kiwi)

On this ample foliage, in May-June, after only the fourth or fifth year of cultivation, small flowers open singly or in threes in the axil of leaves on last year’s shoots. These fragrant flowers have five petals, cream-white to yellowish-white depending on variety. But how to tell a male kiwi plant from a female?

Most Actinidia species are dioecious, meaning they require a male plant nearby for pollination by bees. However, new Actinidia varieties have the advantage of being self-fertile (male and female flowers on the same plant): a single plant is enough to produce fruit. Male/female distinction is simple by looking at the flowers: female flowers are 3 to 4 cm in diameter, solitary and bear short stamens surrounding white stigmas, whereas male flowers are smaller, borne in cymes of three and feature numerous fertile stamens, very prominent, golden and powdery.

Only female plants produce fruit. This flowering is followed by formation of numerous, tasty, ovoid summer berries 3 to 9 cm long: kiwis. Fruit appearance, colour, size and flesh vary between species and cultivars.

About the size of an egg in Actinidia deliciosa and Actinidia chinensis, fruit size is no larger than a gooseberry or a large grape in Actinidia arguta or Kiwai. The thin skin is downy, covered with short brown hairs in Actinidia deliciosa, while it is so smooth in others (Kiwai) that peeling is unnecessary. While the classic kiwi is known for its light-brown skin and almond-green marbled flesh, some varieties produce golden fruit (Actinidia chinensis ‘Minkigold’) or deep-red fruit such as Siberian kiwi ‘Ken’s Red’ or Actinidia deliciosa ‘Kiwi Wonder®’.

Flowers and fruits of the kiwi plant

This juicy pulp, sweeter or tarter depending on variety, contains around 1,000 small black seeds at its centre. Its flavour, tangy and reminiscent of green apple, is rich in fibre, vitamins C and E, carotin and minerals such as magnesium and calcium. The taste of the Kiwai is closer to gooseberry and is sweeter than the traditional kiwi.

Contrary to common belief, kiwi is very hardy, able to withstand temperatures down to −15°C, although young shoots are vulnerable to severe spring frosts. Actinidia arguta, the Siberian kiwi, is perhaps the hardiest, tolerating down to −20°C. Kiwi thrives in sun or partial shade and prefers cool, rich, light, well-drained, non-calcareous soil. This vigorous, hardy climber can be trained against a wall or pergola or will clamber up a tree.

The name “Kiwi” refers to the bird endemic to New Zealand, whose plumage resembles the fruit’s skin.

Self-fertile or dioecious species?

Most new varieties of kiwi (or kiwifruit vine) are self-fertile (‘Solissimo’, ‘Jenny’ or ‘Solo’): a single plant is enough to produce fruit, while others, however, require presence of a male counterpart nearby to fruit. In that case you must plant one male plant or you will have no kiwifruit. Male plants are markedly more floriferous than female plants, do not bear fruit but pollinate female plants: one male plant can pollinate about 5 to 6 female plants at a distance of 5-6 m.

Main species and varieties

Duos

Our self-fertile varieties

Other interesting species

Siberian Kiwi Duo 'Ken's Red' (female) + 'Issai' (pollinator)

Variety 'Issai' with small green fruits is self-fertile and will act as pollinator required for fruiting of 'Ken's Red', which produces small fruits with purplish-red skin and flesh.

• Flowering time July, August
• Height at maturity 5 m

See the full description

Duo of Female 'Hayward' and Male Pollinator 'Atlas' Kiwi Plants

Planting these two kiwifruit near each other gives large tasty fruits with green flesh and good keeping quality.

• Flowering time July, August
• Height at maturity 6 m

See the full description

Hardy Kiwi Geneva (self-fertile) - Actinidia arguta

This variety is the only self-fertile Kiwi arguta. This kiwi is eaten with its smooth skin, no peeling required! Its flesh is sweeter and richer in vitamins than common kiwi.

• Flowering time July, August
• Height at maturity 5 m

See the full description

Kiwi Plant Solissimo (self-fertile) - Actinidia chinensis

One plant is enough to produce an abundant harvest. This variety is very productive!

• Flowering time June, July
• Height at maturity 6 m

See the full description

Kiwi Plant Jenny (self-fertile) - Actinidia deliciosa

A fine self-fertile variety producing small fruits with green flesh. To train along a pergola, trellis or arbour.

• Flowering time July, August
• Height at maturity 6 m

See the full description

Yellow Kiwi Plant Minkigold (female) - Actinidia chinensis

A variety producing golden kiwifruit with yellow flesh and a light apple fragrance. This female plant requires proximity of a male 'Minkimale' plant to allow pollination.

• Flowering time July, August
• Height at maturity 6 m

See the full description

Kiwi Plant Golden Delight (female) - Actinidia chinensis

It's the tastiest of kiwifruit! It produces golden kiwifruit with particularly sweet golden-yellow flesh. It needs Kiwi Golden Delight (male) to fruit.

• Flowering time July
• Height at maturity 5 m

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Yellow Kiwi Plant Kiwi Wonder (female) - Actinidia deliciosa

An original variety with thin, hairless skin that gives yellow fruits with yellow flesh and a red centre, very sweet and without acidity. It requires proximity of a male plant to fruit, such as male cultivar Tomuri.

• Flowering time June, July
• Height at maturity 5 m

See the full description

Hardy Kiwi Ken's Red (female) - Actinidia arguta

This not self-fertile variety produces red kiwaïs with slightly purplish flesh that are eaten with the skin. It's a female plant requiring presence of a male plant nearby to allow pollination.

• Flowering time July, August
• Height at maturity 5 m

See the full description

Planting

Where to plant kiwi?

Perfectly hardy, kiwi can tolerate temperatures down to around -15 °C. However it is sensitive to severe late frosts, since buds freeze at -4 to -5 °C. Give it a sheltered spot, protected from cold winds and spring frosts that can scorch its young shoots and damage its flowers. Avoid north- or east-facing walls in particular.

Kiwi prefers sunny but not scorching positions, especially in southern France. It likes rich, deep soil, not too calcareous to avoid chlorosis, well drained and remaining cool at depth. It dislikes waterlogged, oxygen-poor soils that retain water in winter. It will naturally take to a raised bank if your ground holds too much water in winter.

Kiwi needs room to establish, and for species that are not self-fertile you will need two specimens (a female young plant and its pollinator) for fruit to set.

Training kiwi is necessary: provide a sturdy support about 5 to 6 m long and 3 m high so its stems can climb.

It can be trained on a wall with strong wire, wire mesh, a pergola, a well-sited arbour, or run between two tree trunks. It naturally belongs in an orchard.

When to plant?

Ideally plant kiwi in autumn, October to November. In regions with severe winters it is preferable to plant in spring. In temperate zones, our young plants in containers can be planted all year round outside frost periods.

How to plant?

In the case of varieties of kiwis and kiwaï that are not self-fertile, plan on planting at least one male for five female plants, keeping a planting distance of 2 to 3 metres between plants.

Planting:

• Loosen soil well to 80 cm in all directions
• Dig a hole 3 to 5 times wider than the rootball
• Spread a layer of gravel at the bottom of the planting hole
• Place the rootball in the hole, leaving the collar at ground level
• Backfill with a mix of garden soil, sand and potting compost enriched with a good spadeful of well-rotted compost
• You can also add horn meal
• Provide a support to help its stems climb
• Firm soil and water copiously, then regularly during the first year after planting

Kiwi trained on wire mesh

Maintenance, pruning and care

Kiwi prefers soils that always retain a little moisture: it needs water. Water regularly in summer and during first three years. In periods of high heat, water 1 to 2 times a week. Mulch the base to maintain good coolness. Kiwi needs a fertile soil to produce well: every spring, at flowering, make an application of special fruit tree fertiliser and add compost in March at the base of the kiwi.

Protect base with a good layer of straw for the first three winters.

Do shallow hoeing to keep base clean and prevent germination of adventive weeds.

Train the liana as it grows.

Pruning of kiwi and kiwaï:

When and how to prune?

Pruning plays an essential role in fruiting of the kiwi vine. Kiwis are borne on shoots of the year; pruning promotes fruiting. It is also a voluble plant that can quickly become invasive. Pruning is therefore necessary to encourage branching and control its development. Two types of pruning are recommended:

• Winter pruning

In early years, during winter, from December to mid‑February, simply remove obstructive shoots and shorten secondary branches before growth resumes.

Just after harvest, each year in October–December, cut back by a quarter the branches that bore fruit: leave 2–3 buds after the last cluster of harvested fruit.

Shorten other shoots leaving 3–4 buds.

Keep some main branches that will form the framework.

• Summer fruiting prunings

-In July, when fruits are barely larger than a cherry:

Remove fruits that are too small, keeping only 4 fruits per cluster.

Pinch new shoots back to 4 leaves after the last fruit.

Remove suckers to increase fruit calibre.

-In August: prune back branches pruned in July, leaving only 2 leaves on the new growth.

• Maintenance pruning

1. Every 3 or 4 years, cut back shoots that have lost vigour to 3 cm from the scaffold branch
2. On mature specimens, after 10 years of cultivation, cut old wood at the base above a shoot
3. On male plants, simply shorten the length of the shoots

→ Find all our advice: “Kiwi pruning: when and how to prune an Actinidia?” and “train a kiwi vine“.

Actinidia arguta in autumn

When and how to harvest kiwis and kiwaï?

Once your kiwis are planted, remember that you will need to wait about 4 to 5 years before being able to harvest fruit for the first time.

Depending on variety, kiwi harvest takes place between September and December, up until first frosts. Harvest them in dry weather. You can pick them while still green because they continue to ripen after harvest. Harvest of Kiwaï takes place from late September and during October.

A young kiwi plant will produce about 10 kg, then up to 30 to 50 kg of fruit per year after 10 or 12 years of cultivation.

How to store kiwis?

These “plant mice” will only keep for a few days at room temperature or, in the fridge, for around fifteen days after harvest. They can also be stored in cool conditions for several months between 2 and 5 °C in a cool, airy cellar or larder free from damp or possibly frozen.
To speed up ripening, place kiwis near apples or bananas.

Benefits and uses of kiwi

Low in calories (47 kcal per 100 g), kiwi is best enjoyed fresh, with a spoon, simply halved or peeled. Good for your health, this fruit is a concentrate of vitamins, notably vitamin C (more than oranges!) and vitamin E, and it is also rich in fibre and trace elements. Its black seeds contain omega-3s. Kiwaï is sweeter than regular kiwi and also richer in calcium and vitamin C.

It is a fruit with antioxidant properties, protective against cardiovascular disease.

Once peeled, its tangy, sweet flesh enhances the flavour of desserts such as fresh fruit salads and lends itself to making jams, compotes, tarts and sweet-and-savoury dishes.

Diseases and potential pests

Grown in good conditions, Actinidia is hardy and not very susceptible to disease or parasitic attack. Rarely diseased, it can nevertheless be susceptible to bacterial necrosis (pseudomonas syringae and viridiflava) if soil is too wet: ensure good soil drainage, avoid wetting leaves, remove affected parts, carry out clean, sharp pruning, use horsetail decoctions.

If soil is too calcareous, chlorosis may appear, causing leaves to yellow.

Red spider mites also cause leaves to yellow, then dry out and fall. They thrive in warm, dry conditions: do not hesitate to mist foliage to control them.

→ Learn more about kiwi diseases and pests in our advice sheet !

Propagation

Kiwi propagation can be carried out either by propagation by cuttings or by layering. Grafting is very reliable but is a technique mainly for professionals.

Propagation by cuttings

Propagate kiwi by taking semi-woody cuttings in summer.

• Take a semi-woody shoot about 15 cm long from the tip of the current year’s growth
• Remove leaves from the base of the stem, leaving only two at the tip
• Place the cutting in a mix of turf and sand
• Keep the cutting enclosed and warm at 25 °C, maintaining a humid atmosphere throughout winter
• Plant the rooted cutting the following spring

Discover more advice with How to propagate a kiwi? Our tips for success and Propagate your plants successfully

By layering

Its branches are very long, which makes layering very easy!

• In spring, bend a flexible branch into the soil at the base of the plant
• Remove leaves and scrape the bark for 5–10 cm on that part of the stem
• Bury it in a 10–15 cm deep furrow close to the mother plant so it can root
• Cover with compost and secure the layer
• Lift the end of the branch and stake it
• When the layer has developed sufficient roots you can cut it off just below to separate it from the mother plant, then plant out in open ground

Companion planting for kiwi

Kiwi is planted in orchards as well as ornamental gardens. It should be trained as an espalier. It adapts perfectly to pergolas, trellises, dresses walls or will naturally coil around trees. It is both a fruit tree and ornamental, thanks to its lush foliage and fruits hanging right through to the onset of winter.

An espaliered Actinidia on a structure

It pairs well with Schisandra Chinensis, another fruiting and decorative liana that, like it, prefers moist soil and a sunny to semi-shaded position, or with a Goji (Lycium barbarum). To create a fruitful trellis through the seasons, add it to honeyberries.

In an orchard, plant it near Asimina triloba or “Paw Paw”, small fruit tree with tropical looks, or near a Strawberry Tree with its round, strawberry-like fruits.

Perennial groundcovers such as creeping bugles and Heucheras will keep its roots cool all summer.