A deciduous climber, the Actinidia arguta is grown for its edible fruit and attractive foliage that produces pleasant-scented flowers. The fruits have excellent flavors and are slightly sweet. This is a kiwi cultivar that is disease resistant, and it boasts gorgeous foliage all summer.
I. Appearance and CharacteristicsÂ
Actinidia arguta, the hardy kiwi, is a perennial vine native to Japan, Korea, Northern China, and the Russian Far East. It produces a small kiwifruit without the hair-like fiber covering the outside, unlike most other species of the genus.
Actinidia arguta was first described by Philipp Franz von Siebold and Joseph Gerhard Zuccarini in 1843 as Trochostigma argutum. It was then moved to the genus Actinidia in 1867 by Friedrich Anton Wilhelm Miquel after the invalidly published suggestion by Jules Émile Planchon to move the species.
The fruit is referred to as the arctic kiwi, baby kiwi, cocktail kiwi, dessert kiwi, grape kiwi, hardy kiwifruit, kiwi berry, northern kiwi, Siberian gooseberry, or Siberian kiwi, and is an edible, berry- or grape-sized fruit similar to kiwifruit in taste and appearance, but is green, brownish, or purple with smooth skin, sometimes with a red blush. Often sweeter than the kiwifruit, hardy kiwifruit can be eaten whole and do not need to be peeled. Thin-walled, its exterior is smooth and leathery.
The fast-growing, climbing, twining vine (bine) is very hardy (hence the name hardy kiwi), and is capable of surviving slow temperature drops to −34 °C (−30 °F), although young shoots can be vulnerable to frost in the spring. The vines need a frost-free growing season of about 150 days, but are not damaged by late freezes, provided that temperature changes are sufficiently gradual to allow plants to acclimate. Indeed, a period of winter chill is necessary for successful cultivation. However, rapid freezes kill off buds and split vines. The vines can also be grown in low-chill areas.
While hardy kiwi may be grown directly from seeds (germination time is about one month), propagating from cuttings is also possible. Growing from seeds needs a period of cold stratification of one to two months to germinate. Hardy kiwi cuttings may be grafted directly onto established kiwifruit rootstock, or rooted themselves.
In domestic cultivation, a trellis may be used to encourage horizontal growth for easy maintenance and harvesting; however, vines grow extremely quickly and require a strong trellis for support. Each vine can grow up to 20 ft in a single season, given ideal growing conditions. For commercial planting, placement is important: plants can tolerate partial shade, but yields are optimized with full sunlight. Hardy kiwi vines consume large volumes of water; therefore, they are usually grown in well-drained, acidic soils to prevent root rot.
II. Types of Hardy Kiwi
- Actinidia arguta ‘Anananzaya’ 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.
- Actinidia kolomikta ‘Arctic Beauty’ creates a landscape spectacle with its white and green variegated foliage. This male cultivar is used to pollinate female plants. This variety is hardy down to USDA zone 4.
- Actinidia arguta ‘Issai’ is the only hardy kiwi that is self-pollinating and does not need a separate male for pollination. 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.
III. How to Grow and Care
Sunlight
Hardy kiwi vine can tolerate a range of light conditions, from sun to shade, but in order to flower and produce fruit, this plant needs a full sun location. In varieties with variegated leaves, full sun also results in superior color.
Temperature and Humidity
Unlike its warm weather-cousin, hardy kiwi can survive winter in most areas, but it is susceptible to damage from early season frosts. For this reason, choose a planting site that is not in a frost pocket or subjected to particularly cold wind in the spring. Wind can also damage vines, so plant in a sheltered location. Once it reaches dormancy, however, hardy kiwi vine can tolerate temperatures as low as -25 degrees Fahrenheit. High-temperatures at or over 86 degrees Fahrenheit, on the other hand, can scald leaves and cause heat stress.
Watering
Keep the soil around your newly planted hardy kiwi continuously moist until established. Hardy kiwi relies on at least one inch of rainfall every 10 days, especially right after planting. If your climate provides this, supplemental watering is generally not needed. Weekly waterings are recommended during dry spells or in dry climates. About one gallon of water per plant, delivered through drip irrigation, should do the trick.
Soil
Plant kiwi vines in rich, loamy, well-drained soil. Most vining fruit thrives in garden beds amended with organic matter, such as manure or compost. Hardy kiwi does best in soil with a pH around 5-6.5.
Fertilizing
This vigorous vine is a heavy nitrogen feeder, so make sure to provide adequate nutrients. Three inches of compost added each spring to the base of the plant should provide all the nutrients necessary for the season. You can choose from a variety of appropriate products to give the fruiting plant what it needs, like aged mushroom compost, aged manure, or a rotted pine bark and aged manure mixture.
Pruning
It’s best to prune hardy kiwi vines in winter to promote fruit production. In the first year after planting, select the most vigorous and straight shoot, designating it as the permanent trunk. Cut back the other shoots to encourage vigor in the trunk. Prune as needed during the summer to remove excessively long shoots or overgrown sections. Before the winter, cut back the stems, leaving only 8 to 10 nodes on each.
Propagation
Propagating hardy kiwi from cuttings is the preferred method used, as the cutting yields the same-sex offspring as the parent plant. Gardeners growing kiwi for fruit can easily select both male and female cuttings, should they already know the sex of the parent.
Here’s how to propagate hardy kiwi vine from cuttings:
- Gather gloves, gardening shears, a 4-inch pot with a mix of potting soil and vermiculite, and rooting hormone powder.
- During summer, select a 5- to 8-inch softwood cutting, 1/2 inch in diameter, and snip it just below the leaf node.
- Remove the leaves from the lower part of the cutting, leaving just one set at the top. Poke a hole in the potting medium.
- Dip the cutting into the rooting powder and place one inch of it into the hole; backfill it to set.
- Water the pot, let it drain completely, and then relocate it to a warm, sunny indoor area (preferably a greenhouse).
- Rooting should occur in six to eight weeks. Harden off the plant before transplanting your cutting outside when it is 4 feet tall.
How to Grow From Seed
Most gardeners choose not to grow kiwi vine from seed, especially if they are hoping for fruit. Growing from seed does not assure the sex of the new plant.
That said, you can still grow hardy kiwi from seed if you’re looking for a pretty vining foliage plant and are willing to mimic the conditions needed for stratification. To do so, extract the seeds from the fruit, rinse off the pulp, and dry them on a paper towel for two days. Next, place the seeds in a resealable plastic bag with moist seed-starting mix, and put them in the refrigerator for four months, misting the mix as needed.
In the spring, plant the seeds in a seed tray filled with moist soil and place them in a sunny window until they germinate. Thin seedlings, and then continue misting the soil and growing the strongest plants until the last frost has passed. At that point, harden off the plants before transplanting them outside in a prepared garden bed.
Overwintering
Most varieties of hardy kiwi can withstand winter temperatures as low as -25 degrees Fahrenheit, but still, it’s necessary to protect them if you want a fruitful harvest. Young kiwi vines that are in the ground need only a little extra care. Simply wrap the trunks with frost protection or mound soil and leaves at its base.
After a few years of overwintering, your plant should grow hardy enough to withstand cold temperatures without care. In the spring, make sure to protect new shoots from late-season frosts with a cover or blanket, as hardy kiwi sets fruit on the current season’s growth. Any damage to this growth can affect your harvest.
Pests and Diseases
Common Pests & Plant Diseases
Hardy kiwi vine can suffer from both pests and disease infestation. Keep an eye out for critters—like the Japanese beetle, leafroller caterpillars, root-knot nematode, and snails—which may feed on the plant or fruit. Cover your crop during the fruiting season to keep pests away.
Infestations from bugs, like thrips and two-spotted spider mites, rarely kill the plant, but can be treated with soap and water or a neem oil spray. Avoid the use of pesticides on fruiting plants, as their use can pose harm to yourself, as well as the plant’s pollinators.
Hardy kiwi can also fall victim to fungal diseases, like phytophthora crown and root rot, when neglected. Both conditions present as reddish brown roots and crowns and can be prevented by proper soil moisture management. Botrytis fruit rot can also affect the fruit of your kiwi and cause gray mold and shriveled fruit. There is no treatment for this disease, only prevention, and fungicide use is harmful to those who eat the fruit.
Common ProblemsÂ
Other issues that affect hardy kiwi vine are linked to the plant’s growth habits or damage from wildlife. The leaves and flowers can be damaged by spring frosts, and frost on flowers can mean no fruit that season. So, make sure to cover your plant’s new growth should a cold front move in during the spring.
Rabbits may eat the branches in the winter and deer and gophers may eat the leaves. Birds and other animals often target the fruit as it ripens. Covering the plant will help with these issues, as well.
III. Uses and BenefitsÂ
- Culinary uses
Korea
In Korea, hardy kiwi is known as darae (다래). Young leaves, called darae-sun, are often consumed as namul vegetables.
China
In China, it is known as 软枣猕猴桃. This species is strongly differentiated and widely distributed across China. It is distributed in China from the Heilongjiang River in the north to the Wuling Mountains in Guangxi in the south. It is a seasonal fruit, usually sold at farmer’s markets
