There are a couple species of Hardy Kiwi (also called Kiwiberry) vines that will grow and produce in Philadelphia. Hardy Kiwi (Actinidia arguta) is a perennial fruit vine that can grow up to 30 feet tall. Originally native to Asia, this cold-tolerant and easy to grow species can be grown in zones 3-8. The vine produces a sweet edible fruit with a beautiful green color, smaller but similar in flavor to its more familiar subtropical cousin, the Fuzzy Kiwi (Actinidia deliciosa). The grape-sized fruits are arranged in clusters and have a smooth, thin skin so they can be enjoyed whole without peeling. POP enjoys planting this vine at our partner sites because it can grow on vertical structures often utilized in compact urban growing environments such as walls, trellises, fences, and pergolas. It grows well in direct sunlight to partial shade and can be a great option for growers who are interested in bringing some decorative and shady areas to their urban growing environment. Harvest occurs in late summer to early fall, depending on the variety. The delicious fruit can be kept refrigerated for a few months if harvested when firm.
Arctic Beauty Kiwi (Actinidia kolomitka) is another cold hardy variety of Kiwi, and an entirely different species from the Hardy Kiwi. More information can be found below (under cultivars).
Is it invasive?
There has been some controversy about Hardy Kiwi (Actinidia arguta) in recent years, particularly in the the Northeastern United States. In a few places in Massachusetts, New York, and New Jersery, environmental groups have been fighting these vigorous vines taking over forest trees. After years of investigation, the Massachusetts Department of Agriculture concluded that it should not be added to the invasive list, as the affected areas are limited in scope and the result of abandoned plantings from when the species was widely planted as an ornamental vine in the 19th century, with little evidence of seed dispersal. However, New Jersey recently added Hardy Kiwi to its list of invasive plants. Caution and judgement should be used in whether and where to plant these vigorous vines.
Growing conditions:
Hardy Kiwi can grow in sun or partial shade, but full sun is preferable for best production. The vine prefers rich, well drained, and loamy soil of pH 5-6.5 that can be enriched with compost. Plant hardy kiwi vines at least 10 feet apart in the spring or fall, when there is no danger of frost. It is important to select one or two new canes and train them to grow vertically to their support structure. Do not allow them to twist around themselves or the support pole or wire.While the vine will begin to grow in its first season, it will usually take at least three years before fruiting.
Like many of the younger fruit trees we plant, hardy kiwi requires consistent watering for the first year until it is established. Right after planting, hardy kiwis need at least one inch of rain every 10 days, or weekly watering during dry spells. Though hardy Kiwi can survive winter in most areas, the plant can suffer damage from early frosts and wind in colder regions. For this reason, choose locations that are not known frost pockets or subjected to heavy wind conditions. High heat over 85 degrees fahrenheit can also sometimes cause heat stress.
Hardy Kiwi Cultivars and Pollination Requirements:
Most hardy kiwi cultivars are dioecious, which means they bear either male or female flowers. For this reason, separate male and a female plants are needed in order to produce fruit. Male vines do not fruit, but at least one for every 7 female plans is needed for pollination.. There are also a few self-pollinating cultivars which bear flowers of both sexes, but their fruit quantity and quality is somewhat lower..
There are many cultivars of hardy kiwi available, but here are some of the more commonly planted ones:
- Actinidia arguta ‘Anananzaya’ or ‘Anna’is a vigorous grower with very sweet fruit. Also called ‘Anna,’ this female plant is hardy down to USDA zone 4 and is one of the best fruit producers. Fruits are relatively large and firm, with excellent flavor. They ripen late in the season and are reliably productive
- ‘Dumbarton Oaks’ is a female variety that produces relatively large, flavorful fruit. This variety ripens a few weeks before the ‘Anna.’
- ‘Geneva’ is a female variety with excellent flavor and early ripening, also about three weeks before the ‘Anna.’
- ‘Issai’ is a hardy kiwi that is self-pollinating and does not need a separate male for pollination, though some growers note that growing a male pollinator can increase fruit size and set. It is hardy down to USDA zone 5 and requires less pruning than other varieties due to its limited growth habit. The fruit is smaller than other hardy kiwi, and the vine is less vigorous.
- ‘Prolific’ is another self-fertile variety. It is easily trained for trellises and fences and will independently yield delicious, grape-sized fruit. Unlike other varieties that take a few years to bear fruit, the Prolific can bear fruit the first year after planting.
- ‘Ken’s Red’ is one of the largest varieties of hardy Kiwi available. It is also a variety that has red fruit instead of green. The plant is hardy from zones 3-9 and bears fruit in 3-4 years after planting. The fruit is fairly large and cylindrical.
- Actinidia kolomikta or Arctic Beauty vine, is a different species from the Hardy Kiwi. It creates a landscape spectacle with its white and green variegated foliage. Slightly smaller and less vigorous than the hardy or fuzzy kiwi and happier with some shade, you can use Arctic Beauty to cover the north side of a fence, arbor, or trellis. This male cultivar is used to pollinate female plants. This variety is hardy down to USDA zone 4.
Structures, Training, and Pruning
Pruning and Training
Like most of the trees, vines, and brambles we work with at POP, we prune hardy kiwis in the wintertime. Pruning in the wintertime is ideal because you can see the entire structure of the plant. In addition, pruning keeps this vigorous plant from strangling itself and promotes fruit production during the growing season. In the first year after you plant your vine, select a strong shoot that is growing in an ideal direction and designate it as the permanent trunk. Because the fruit grows on all new growth, the rest of the plant can be pruned aggressively- up to 90% of growth can be removed each winter. Cut back other shoots to encourage the vigor of the permanent trunk, generally leaving a couple of permanent side arms growing on the structure, with young laterals spaced every 1’ growing off of that. You may also want to prune during the summer to control the spread and density of the vine, as they grow very vigorously. Two or three times during the summer, cut nonflowering laterals back to the outside wire on the trellis or width of the support structure.
Structures
A few recommended structures for growing kiwis are fences, arbors/pergolas, and t-trellises. While each option offers something slightly different, these structures ensure efficient fruit production, easy harvesting, space management, and sun and airflow to reduce pest and disease pressure. Fences are a great option for urban growers who want to grow on an already existing fence on site, or are choosing to install a fence to protect the orchard space. Arbors/ pergolas are an excellent option for gardens and farms that do not have a lot of shade cover. Planting a hardy kiwi and allowing it to vine up and over the pergola will bring shade and beauty to any garden space. Lastly, T-Trellises, with posts perpendicular to the ground and wires running horizontally in between posts, promote the organization to growth of an otherwise unruly kiwi vine. For more information about building trellises, see our earlier blog post, “Lean on Me:” an overview of Orchard Trellis Systems.”
Growing Challenges
Kiwiberries are one of the easiest fruits to grow, having little to no pest or disease problems. Although POP partners have not reported any of the following growing challenges, it is good to be aware of and monitor for them. Insects such as japanese beetles and leafroller caterpillars can sometimes do some damage and snails can occasionally feed on the vegetation or fruit. Infestations from these pests can damage the plant, though rarely if ever kill the plant. An organic option to mitigate infestations of these pests is neem oil spray.
Fungal diseases such as phytophthora crown and root rot can also potentially pose a threat to hardy kiwi. Both fungi present as reddish brown roots and crowns. Proper soil moisture management can prevent fungal infection. Botrytis fruit rot can also affect the fruit of your kiwi and cause grey mold and shriveled fruit. There is no treatment for this disease, only prevention.
Harvesting
Our post, “Late-Season Ripeners: a How-to on harvesting and preserving Jujubes, Persimmons, Medlars, Hardy Kiwis, and Gojis,” by Robyn Mello, offers information on how to harvest kiwi berries. Robyn writes, “Hardy kiwis don’t ripen all at once, even within the same cluster, so test out a few before harvesting them all at once. When the first fruits start to soften to your touch, you can harvest them all and have them soften to desired ripeness in your kitchen. Often called kiwiberries, these fuzzless fruits can be eaten whole like grapes rather than skinned like most fuzzy kiwis you find in grocery stores. If you have an excess, consider making kiwi tarts, jam, or wine. Be careful, though, heating will muddy the vibrant, green color.”
Sources:
Hardy Kiwifruit (Cornell ECommons)
How to Grow and Care for Hardy Kiwi Vine. (Thespruce.com)
Growing kiwiberry in the home garden | UMN Extension
Uncommon Fruits for Every Garden by Lee Reich
Grow Fruit Naturally by Lee Reich
DISCLAIMER
The information presented on this website is for informational, reference, and educational purposes only and should not be interpreted as a substitute for diagnosis and treatment by a health care professional. Always consult a healthcare professional or medical doctor when suffering from any health ailment, disease, illness, or injury, or before attempting any traditional or folk remedies. Keep all plants away from children. As with any natural product, they can be toxic if misused.
This POP Blog was written by Program Coordinator Julian D’Andrea with help from Co-Executive Director Phil Forsyth.
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