Kiwifruit, Actinidia spp.

Fruit of Actinidia deliciosa.

The kiwi is a flightless bird native to New Zealand, a name New Zealanders like to call themselves, and also a fruit – one of the very few temperate fruit crops to have been domesticated this century. Native to the high grasslands, low scrub and forests of China and Russia, Actinidia deliciosa was still just a wild plant in China (a delicacy called Yang Tao) at the turn of the century. In 1904 seeds were imported into New Zealand (and about the same time into the U.S. and Europe), and after a little selection, the fuzzy brown fruits with green flesh were renamed kiwifruit (from Chinese gooseberry) and developed into a successful export crop. Today the kiwifruit is an important commercial crop in New Zealand, the United States, Italy, Japan, France, Greece, Spain, Australia, and Chile, with the more than a million tons of fruit per year distributed worldwide.

‘Hayward’ kiwifruit.

Most of the kiwifruit grown in commercial orchards outside of China are a single variety, ‘Hayward,’ descended from two female plants and one male plant derived from a single introduction of seed. Grafted plants were first sold in the 1920’s, standardizing the type of fruit produced. ‘Hayward’ has large, oval fruits with bright green flesh that lack a hard or woody core.

But this is not the only type of kiwifruit. The genus Actinidia contains about 60 species. All are perennial, mostly deciduous, climbing woody vines native to Asia, but their fruit is quite variable. Some produce fruits singly, others in bunches. The fruits vary in size, shape, hairiness, and color. The flesh can also vary in color, juiciness, texture, and taste, with some fruits being basically inedible while others are considered better than the standard kiwifruit.

Fruit diversity in Actinidia, with the commercial kiwifruit, A. deliciosa ‘Hayward’ for comparison.

1  A. rufa 5  A. latifolia 9  A. arguta 13  A. guilinensis
2  A. melanandra (red kiwi) 6  A. indochinensis 10  A. fulvicoma 14  A. setosa
3  A. glaucophylla 7  A. chinensis ‘Hort16A’ 11  A. deliciosa ‘Hayward’ 15  A. chrysantha
4  A. chinensis 8  A. macrosperma

12  A. arguta var. purpurea

(purple kiwi)

16  A. eriantha
Photo from Ferguson, A.R. 1999. New temperate fruits: Actinidia chinensis and Actinidia deliciosa. p. 342–347. In: J. Janick (ed.), Perspectives on new crops and new uses. ASHS Press, Alexandria, VA. Online at http://www.hort.purdue.edu/newcrop/proceedings1999/v4-342.html

Red, yellow and green kiwifruit cultivars. Photo by New Zealand Plant & Food Research.

In the 1980’s a new commercial, yellow-fleshed variety was created in New Zealand by crossing the conventional A. deliciosa with A. chinensis, which comes from warmer parts of China. This smooth-skinned Vespri Gold cultivar — with a sweeter, more tropical taste and higher vitamin C content than the common ‘Hayward’ variety — was released in 2000. A. arguta has been introduced commercially in New Zealand, and other cultivars may be developed.

Commercial kiwifruit vine in California.

The standard kiwifruit found in your local market is not a tropical fruit as many consumers believe, but does require a long growing season (over 200 days) and cannot tolerate winter temperatures below 10ºF. But this doesn’t mean you can’t grow kiwifruit here in Wisconsin. Some species of hardy kiwifruit will survive temperatures as low as -40ºF, and some produce fruit that are even sweeter and more flavorful than the commercial kiwifruit.

Hardy kiwi, A. arguta. Photo from https://fr.m.wikipedia.org/wiki/Fichier:Weiki02.jpg

The two most commonly available hardy species are A. arguta and A. kolomikta. A. arguta (with common names including Hardy Kiwi, Bower Vine, Dessert Kiwi, Cocktail Kiwi, Tara Vine, Yang Tao) produces smooth and hairless, grape-sized fruit in reds and greens with a sweet flavor similar to the commercial kiwi. A. arguta has a strong-growing vine to 40 feet, with dense, dark green foliage. In its native Asian habitat the vines typically grow wild in trees, climbing as high as 100 feet. When fully dormant the plants can withstand -25°F (Zone 4), but they still need a long growing season (about 150 frost-free days) and must acclimatize to cold. Sudden temperature drops may cause trunk splitting and subsequent damage to the vine. Young shoots, flower buds, and flowers are vulnerable to frost injury, and can be damaged in as little as 30 minutes at 30°F. The plants can be grown in large containers, however, to provide suitable temperatures, but do need a certain amount of winter chilling. There are many varieties of A.arguta; probably the most popular is ‘Ananasnaya,’ commonly called ‘Anna.’

Leaves of the male super-hardy kiwi, A. kolomitka.

Super-hardy kiwi, A. kolomikta, is even more cold hardy, tolerating temperatures to -35 or -40°F (Zone 3) but is much less vigorous than A. arguta, growing only to about 20 feet. It produces fruit similar to A. arguta but somewhat smaller. ‘Arctic Beauty’ is a commonly-offered variety. The male vines develop attractive pink, white and green variegated leaves the second to third year after planting.

Female flower of A. deliciosa.

The white to cream flowers are produced in the leaf axils, singly or in small groups for a period of several weeks in late spring. All species appear to be dioecious (with both male and female parts on a single plant), but are functionally monoecious (male and female parts on different plants). Flowers on male vines produce viable pollen but lack a fully developed stigma and ovary, while the flowers of female vines don’t have viable pollen. The one exception is the self-fertile variety ‘Issai,’ which tends to have small fruit and relatively low vine vigor. The transfer of pollen from male to female flowers is essential for fruit production and fruit set of the female flowers depends on adequate pollination by bees or other pollinators. One male vine may supply enough pollen for four females. Female flowers are viable and receptive to male pollen up until 9 days after opening, while the pollen from male flowers is viable for only 3 days after opening. Home gardeners can hand pollinate by picking a freshly opened male flower and rubbing it on a viable female flower for a second or two. One male flower can be used on as many as five female flowers before discarding it.

Hardy kiwifruits ripen in late summer to late fall, depending on the cultivar and local weather conditions. The fruits drop or come off easily when they are fully ripe. However, they are usually picked at the mature-ripe stage and allowed to ripen off of the vine as for the commercial types. Store-bought kiwis are ready to eat when slightly soft to the touch. The firmer the flesh the more tart the flavor will be. To speed up the ripening process, place the fruit in a bowl with ethylene-producing fruits such as apples, pears or bananas.

Commercial kiwifruit orchard and ripening fruit.

Espaliered hardy kiwifruit vine.

All kiwifruit plants require a wall, fence, substantial trellis, other permanent place to grow upon (even in trees) since the long-lived plants climb by twining. The vines do best in a sunny location with well-drained, somewhat acid (pH 5 - 6.5) soil. Vines grow and produce best in areas sheltered from constant or gusty winds. Winds of only 10 to 15 miles per hour or can break developing shoots and reduce vine growth and production. Tall hedges are used in New Zealand kiwifruit orchards to help reduce wind damage. The plants need constant moisture, but not soggy soil, and are heavy nitrogen feeders. Winter pruning is necessary for good fruit production.

Hardy kiwis don’t have many pests or diseases, but deer will browse on the leaves and rodents may attack the roots. And cats may damage the plants since they love to rub against the catnip-scented trunk – this activity will damage new shoots emerging in the spring on small plants!

– Susan Mahr, University of Wisconsin – Madison


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Additional Information

  • Hardy Kiwifruit – on the California Rare Fruit Growers webstie
  • Kiwifruit – on the Purdue University New Crop Resource Online Program website

18 comments

  1. I would love to grow some kiwis, especially the A. arguta. The small berries remind me of kumquats. Easy to pop in the mouth and no peeling required! I wonder if they would train well up a chain-link fence.

  2. Always thought of kiwi being a more topical fruit native to New Zealand! Did not realize there are so many varieties although I have seen the yellow kiwis at the grocery store. Interesting article.

  3. incredible article as I enjoy eating Kiwi and really did not know that much about them. Might even attempt to give them a shot in the garden.

  4. Fascinating article. Didn’t realize there was a yellow flesh variety! Would love to try growing one of the hardy varieties.

  5. I never knew there were Kiwi varieties for our WI region! I am excited to research which may grow best in my area (zone 4) but suspect Hardy Kiwi will be the best choice. 2019 is going to be an exciting year!

  6. Nice article, also to know that you can ripen them faster with using bananas, apples and pears. I will pass that on to a few of my friends. I also didn’t know that the trunk smelled like catnip. My cat would love this plant.

  7. When the article mentioned deer that became a red flag for me as I live where the numerous deer roam freely. However, I would really like to grow these unique fruit. Super-hardy kiwi, A. kolomikta, would be the one I would choose. Thanks for info.

  8. I enjoy eating kiwi and was surprised by the photo of the many sizes, shapes and colors. Unfortunately the space needed to grow them and their lack of wind tolerance make them unsuitable for me to grow them. 🙁

  9. I only know of the kiwi I buy in the produce aisle. Was not aware of all the varieties. My yard is too tiny to add all the new fun things able to be grown in WI.

  10. I have grown one from seed that had gotten over 6 feet tall. I accidentally killed it last year.
    Very interesting article.

  11. I do enjoy eating the kiwifruit as it is tasty for sure. I have thought about growing zone hardy kiwis in my area which is a zone 3-4. I found them available in a nursery catalog. Currently, I do not have the space for a 20-40 foot vine depending on the variety I would plant. I also have some windy conditions to consider. I didn’t realize there were that many varieties. Many of them have attractive foliage and leaves. They would be a nice addition to the yard. I am wondering how well they do for providing for the native insects and wildlife since they are a non-native plant. Do local insects and animals benefit from them in any way?

  12. Kiwi is a very interesting fruit. I did not realize there was such a variety of different cultivars. Since it can be grown in Wisconsin it might make an interesting change from our normal plants we cultivate.

  13. I had no knowledge about the Kiwi plant before reading this, very informative.

  14. Kiwi is one of my favorite fruits. And I was surprised to learn that they can grown in Wisconsin. Sounds like they might be temperamental in this zone. I think I will stick to my apple and cherry trees and leave the kiwi for buying at the store.

  15. I would love to try to grow one, but not being deer resistant, cats like to rub, and not having an area that is not protected from the winds without being heavily shaded is a reason I may not be able to…but I still may try the kolomikta, as it is hardy. That is what I would require as it gets cold where I live in far northern WI.

  16. It’s surprising to read that kiwi vines can grow in Wisconsin. I’m tempted to try growing them on the trellises in my back yard, which are next to the neighbor’s solid fence. I have some shrubs I’m trying to grow near the fence, so perhaps kiwi could grow in between. I’ve downloaded the pdf. Thanks.

    Weird. You have my new e-mail, but the form autofilled with my old e-mail. I’ve been really struggling to get rid of the old e-mail. I’ve had numerous techies trying to help me, and it just keeps coming back.

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