The classification of the genus Actinidia is difficult and the taxonomy of some taxa is still confusing. Various studies since 1984 have estimated the genus to comprise anywhere between 54 - 76 species. The species of Actinidia are highly variable in their vegetative structures, as well as in their flowers and fruits, which is the main reason for the difficulty in the classification of the genus. A detailed study of the genus, based on a wide range of specimens, is needed to clarify the situation and it could be many more years of work until a natural classification system is found - Xinwei LI, Jianqiang LI, Djaja Djendoel SOEJART; Advances in the study of the systematics of Actinidia Lindley; Front. Biol. China 2009, 4(1): pp 55 - 61.
The treatment followed here is based mainly on the Flora of China[], with some later amendments[].

Common Name: Kiwi Fruit

General Information

Actinidia deliciosa is a large deciduous, climbing shrub producing producing one or more branched stems that twine into the surrounding vegetation for support or scramble over the ground where they can form dense thickets[].
The Kiwi fruit is widely grown both commercially and in gardens for its edible fruit, which is traded internationally.

Known Hazards

Generally a very wholesome and healthy food, the fruit does contain relatively high quantities of the highly active proteolytic enzyme actinidin. This does not seem to be a major health hazard for most people, but it can cause damage to the lips (especially at the corners of the mouth) although usually only if very large quantities of fruit are eaten[]. Peeling large numbers of fresh fruit can result in skin loss if hands are not protected[].
Some people have a sensitivity to the actinidin and are unable to eat the fruit[].

Botanical References

,

Range

E. Asia - southern China

Habitat

Mountain slopes in relatively damp, shady or semi-shady areas in gullies, especially along streams, under the tree canopy, or on the edge of the forest, or in clearings in mixed evergreen-deciduous forests[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Climber
Height	9.00 m
Growth Rate	Medium
Pollinators	Bees, Insects
Self-fertile	No
Cultivation Status	Cultivated

Cultivation Details

Actinidia deliciosa is a fairly hardy plant, tolerating temperatures down to about -20°c when fully dormant, although young growth in the spring is very subject to damage by late frosts and can be killed back at -2°c[, , ]. Plants requires a 6 - 8 month frost-free growing season[, ]. They also require a winter chilling of 600 - 1,100 hours below 7°c and a long warm summer in order to ripen the fruit[].
Prefers a sound loamy acid soil, it dislikes alkaline soils and becomes chlorotic at pH 6 or higher[]. Tolerates a pH in the range 5.5 to 7.3. Succeeds in semi-shade but full sun is best for fruit production[, , ]. Prefers a sheltered position[]. Does well when grown into trees[].
Plants fruit on second year wood or on fruit spurs produced on older wood[], any pruning is best carried out in the winter[]. The flowers are sweetly scented[].
A very ornamental plant[], it is widely cultivated in warm temperate zones for its edible fruit, there are many named varieties[, ]. The fruit can store for up to 9 months at 0°c with a relative humidity of 90%, but under domestic conditions 4 - 6 weeks is optimal[].
Plants have been seen with very good crops of fruit at the Hillier Arboretum in Hampshire, England in several autumns. These plants had outgrown their planned supports and had climbed 15 metres or more into neighbouring trees. The main problem with them would be how to harvest the fruit, since almost all of it was at the tops of the plant[].
The female cultivar 'Heywood' is the most commonly cultivated form in Britain (1993), its fruits store well but it tends to flower late and there can be problems with pollination[].
The cultivar 'Blake' is said to be fast cropping and self-fertile[].
The male 'Tomurii' is free-flowering and disease-resistant[].
Plants in this genus are notably resistant to honey fungus[].
Plants are usually dioecious, but hermaphrodite forms are known. However, the fruit quality and yield of these hermaphrodite forms is usually inferior[]. Male and female plants must usually be grown if seed is required, one male to five or six females is normally adequate.
Female plants produce morphologically perfect flowers with well-developed pistils and stamens, but their stamens produce nonviable pollen; flowers of male plants have small, rudimentary ovaries without viable ovules but their stamens release viable pollen[].

Edible Uses

Fruit - raw or cooked. A delicious flavour[, , , , ], the fruit can be up to 8cm long, it is very juicy when fully ripe and has a refreshing, acid flavour[]. It contains a number of small seeds, but these are easily eaten with the fruit[]. Rich in vitamin C[]. Fresh fruits contain 100 - 420mg vitamin C per 100g and 8 - 14% carbohydrate[]. Acidity is 1 - 2%, mainly citric acid[]. The fruit ripens in November and can store for 3 - 4 months[]. Yields of 8 - 30 tonnes per hectare are possible[].

Leaves are a famine food[].

Medicinal

The fruits, stems and roots are diuretic, febrifuge and sedative[]. They are used in the treatment of stones in the urinary tract, rheumatoid arthralgia, cancers of the liver and oesophagus[].

Other Uses

Paper is made from the bark[].

If the bark is removed in one piece from near the root and placed in hot ashes, it becomes very hard and can be used as a tube for a pencil[].

Propagation

Seed - sow spring in a greenhouse[]. It is probably best if the seed is given 3 months stratification[], either sow it in a cold frame as soon as it is ripe in late autumn or as soon as it is received. Fresh seed germinates in 2 - 3 months at 10°c, stored seed can take longer[]. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in light shade in the greenhouse for at least their first winter. When the plants are 30cm or more tall, plant them out into their permanent positions in late spring or early summer, after the last expected frosts[]. Most seedlings are male[]. The seedlings are subject to damping off, they must be kept well ventilated[].
Cuttings of softwood as soon as ready in spring in a frame[].
Cuttings of half-ripe wood, mid summer in a frame. Very high percentage[].
Cuttings of ripe wood, autumn in a frame.