Hardy kiwi vine is a cold-hardy cousin of the vine that produces the familiar kiwi fruit sold at grocery stores (Actinidia deliciosa). This cold-tolerant cultivar can be grown in USDA zones 3 through 9, depending on the variety. Like its warm-weather cousin, hardy kiwi also produces a sweet edible fruit that is smaller than a traditional kiwi (about the size of a large grape) and can be eaten whole, without peeling. Hardy kiwi is primarily featured in landscapes for its attractive heart-shaped foliage. This climber grows well on strong trellises, fences, pergolas, and other structures.
Hardy kiwi should be planted in the spring after all danger of frost has passed. It will create a visual impact in its first season; however, you'll have to wait at least three years before hardy kiwi produces fruit to harvest.
|Common Name||Hardy kiwi, hardy kiwi vine|
|Botanical Name||Actinidia arguta, Actinidia kolomikta|
|Plant Type||Perennial, fruit|
|Mature Size||10-30 ft. long|
|Sun Exposure||Full, partial|
|Soil Type||Loamy, well-drained|
|Flower Color||Green, white|
|Hardiness Zones||3-9 (USDA)|
Hardy Kiwi Vine Care
Hardy kiwi vine is native to eastern Asia, but will grow well almost anywhere with proper care and sufficient sun. When growing this plant for foliage, shade, or fruit (or all three), train the vine on a sturdy support structure, like a trellis, arbor, pergola, or fence. It can be manipulated to form a broad canopy or to branch out horizontally in espalier form.
When growing kiwi vine for fruit, make sure to plant both male and female plants (you need at least one male for every four female plants), or choose 'Issai', a self-pollinating variety. Keep in mind that the vine typically doesn't fruit for at least three years, and, depending on your conditions, sometimes up to five to nine years. This fast-growing, vigorous vine is rarely invasive, yet it can overcome shrubs and small trees if left unchecked.
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.
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.
Plant kiwi vines in rich, loamy, well-drained soil. While some experts advise planting in poorer soil to control rampant growth, most vining fruit does best 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.
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, A. arguta can tolerate temperatures as low as -25 degrees Fahrenheit, while A. kolomikta can survive -35 to -40 degrees Fahrenheit. High-temperatures at or over 86 degrees Fahrenheit, on the other hand, can scald leaves and cause heat stress.
This vigorous vine is a heavy nitrogen feeder, so make sure to provide adequate nutrients. Three inches of compost provided 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.
Types of Hardy Kiwi
Any variety of hard kiwi vine will make your landscape efforts pop, but choosing the right one for you depends on your growth goals and your desired aesthetic. If fruit is your main focus, select both male and female plants to ensure good pollination and fruit set. One male plant can pollinate four female plants, but timing is tricky. The pollen of male flowers is only viable for three days after opening, while the female flowers are receptive up to 9 days after opening. Bees pollinate the flowers, but you can also hand-pollinate the blooms by taking one male flower and rubbing pollen on up to 5 female flowers before discarding the bloom. Look for cultivars with variegated leaves to blend with your other perennials.
Here are a few gardener's favorites:
- 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.
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.
Propagating Hardy Kiwi Vine
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 Hardy Kiwi Vine 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, and ending up with plants of only one sex is disappointing. 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.
Most varieties of hardy kiwi can withstand winter temperatures as low as -25 degrees Fahrenheit, still it's necessary to protect them, should 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.
Common Pests and 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 grey mold and shriveled fruit. There is no treatment for this disease, only prevention, and fungicide use is harmful to those who eat the fruit.
How to Get Hardy Kiwi to Bloom
If the vine does not bloom, it might not get sufficient sunlight. While the vine can be grown in partial sun, full sun is crucial for flowering and fruiting.
Common Problems With Hardy Kiwi Vine
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.
When should you harvest the fruit of hardy kiwi?
The fruit from hardy kiwi is normally harvested in early fall when it is still hard to the touch, but the seeds are black. Fruit should be eaten immediately or stored in the refrigerator for up to a few weeks.
What are some landscape uses for hardy kiwi vine?
Trained to a supporting structure, kiwi vines can function as privacy screens. However, since they lose their leaves in fall, this is only a seasonal benefit. Variegated varieties can effectively be used as specimen plants. And, the shade tolerance of kiwi plants makes them a good growing option for shady areas where many other vines would not perform well.
Is hardy kiwi invasive?
Although this vine does not grow as large as some others, its fast-growing nature needs to be kept in check, should you not want it to overwhelm other shrubs and small trees. Supervise and control its growth with regular pruning to avoid such situations.
Kiwifruit and Hardy Kiwi. Ohio State University Extension.