Growing Hardy Kiwi (Kiwiberries) in Canada
Grape-sized, smooth-skinned kiwis on a vigorous vine: what it takes to get fruit in a Canadian garden.
Growing hardy kiwi in Canada means choosing the right species and planning for spring frost. The fuzzy grocery kiwi will not survive a Canadian winter. Hardy kiwi, Actinidia arguta, has smooth, grape-sized fruit eaten skin and all, and the University of Wisconsin says a fully dormant vine can withstand about −32 °C (−25 °F, US Zone 4).
An even hardier cousin, Actinidia kolomikta, tolerates about −37 to −40 °C (US Zone 3) with smaller fruit on a much smaller vine. These are US (USDA) hardiness zones, which are built differently from Canadian zones, so a US Zone 4 rating is not the same as a Canadian Zone 4 garden. See USDA vs Canadian zones to compare.
Hardy kiwi at a glance: Plant female vines plus a male (only females fruit), except self-fertile Issai. Build a strong trellis or pergola first. The vine needs about 150 frost-free days, and its spring shoots and flowers are hurt by about −1 °C, so avoid frost pockets. Expect 3 to 5 years before fruit.
Want a fruit tree that ripens in the fall? See Growing Pawpaw in Canada for a native Canadian tree with a custard-like fruit.
Male and Female Vines
The University of Wisconsin explains that kiwis are dioecious: male vines make pollen and no fruit, female vines make fruit but no viable pollen. The exception is Issai, which is self-fertile but tends to have small fruit and low vigour.
Wisconsin says one male can supply pollen for about four females; Ohio State suggests one male for six to eight. Bees do most of the work, but Ohio State warns fruit set can still disappoint and encourages hand pollination: rub a freshly opened male flower on the female flowers. Wisconsin adds that female flowers stay receptive for about nine days, but male pollen is good for only about three.
Ohio State also suggests planting the male upwind of the females, since wind plays a part.
Frost-Free Season, City by City
The University of Wisconsin says A. arguta needs a long season of about 150 frost-free days. Compare that with the average frost-free season in Canadian cities, from this site’s frost data:
| City | Canadian Zone | Average last frost | Average first frost | Frost-free season |
|---|---|---|---|---|
| Victoria | 8b | Mar 10 | Dec 15 | 280 days |
| Vancouver | 8b | Mar 15 | Nov 30 | 260 days |
| Kelowna | 6b | May 5 | Oct 15 | 163 days |
| Windsor | 7a | Apr 20 | Oct 28 | 191 days |
| Niagara Falls | 6b | Apr 28 | Oct 22 | 177 days |
| Toronto | 6b | Apr 20 | Nov 1 | 195 days |
| Montreal | 5b | May 9 | Oct 7 | 151 days |
| Ottawa | 5a | May 9 | Oct 12 | 156 days |
| Halifax | 6a | May 10 | Oct 18 | 161 days |
| Winnipeg | 3a | May 25 | Sep 20 | 118 days |
| Calgary | 3b | May 23 | Sep 21 | 121 days |
| Edmonton | 4a | May 14 | Sep 23 | 132 days |
Frost dates are averages from Environment and Climate Change Canada climate normals, and your own yard can differ. Where the season falls well short, the fruit may not ripen even if the vine survives.
Spring Frost Is the Real Risk
Ohio State calls spring frost the main problem with every Actinidia species: the vines leaf out early, and young shoots and flower buds are injured by brief exposure to about −1 °C (30 °F). Wisconsin says damage can come in as little as 30 minutes. Lose the flowers and there is no fruit that year.
So site matters more than the zone. Ohio State recommends good air drainage, shelter from high winds and a spot that is not frost-prone. Avoid the low corner where cold air settles. Wisconsin also notes sudden temperature drops can split the trunk, and Ohio State suggests protecting young trunks.
Trellis, Soil and Spacing
Hardy kiwi is a big vine: Wisconsin gives up to about 12 m (40 feet) for A. arguta and about 6 m (20 feet) for A. kolomikta. Penn State grows its vines on a sturdy pergola-style T-bar trellis in full sun. Build the support before you plant.
Ohio State reports that many young vines die in their first season, mostly from poorly drained soil and root rot. Choose a well-drained loam, not heavy clay. Wisconsin gives a slightly acid pH of 5 to 6.5, and Ohio State around 6.5. Ohio State spaces vines 4.5 to 5.5 m (15 to 18 feet) apart, because they grow vigorously.
Winter pruning keeps the vine fruitful, and Penn State notes the shoots, especially on males, grow quickly. One odd warning from Wisconsin: cats like to rub against the catnip-scented trunk and can damage new shoots on small plants.
When Does Hardy Kiwi Fruit?
Be patient. Ohio State says most kiwiberry cultivars take three to five years to fruit; Issai is said to fruit in year three. Penn State grows mostly Ananasnaya, often sold as Anna, as its female variety.
The fruit ripens from late summer to late fall. Wisconsin says ripe fruit drops or comes off easily, but kiwiberries are usually picked when mature and ripened off the vine, like grocery kiwis. Eat them fresh, skin and all, once they soften.
Frequently Asked Questions
Can you grow kiwi in Canada?
Not the fuzzy grocery kiwi, but hardy kiwi (Actinidia arguta) can survive about minus 32 degrees C when fully dormant, and Actinidia kolomikta about minus 37 to minus 40.
Do I need a male and a female kiwi vine?
Yes, for most hardy kiwis. Only female vines fruit, and they need pollen from a male. The self-fertile variety Issai is the exception.
How many female kiwi vines does one male pollinate?
The University of Wisconsin says one male can supply about four females; Ohio State suggests one male for six to eight.
How long until hardy kiwi fruits?
Ohio State says most cultivars take three to five years.
Why did my hardy kiwi not fruit?
Common causes are no male vine, a vine still too young, or a spring frost that killed the flowers. Young shoots and flower buds are hurt by about minus 1 degree C.
How long a season does hardy kiwi need?
The University of Wisconsin says Actinidia arguta needs about 150 frost-free days.
Do you peel kiwiberries?
No. Hardy kiwi has smooth skin that is eaten with the fruit.
Sources
- University of Wisconsin–Madison Extension — Kiwifruit, Actinidia spp.
- The Ohio State University Extension — Kiwifruit and Hardy Kiwi (Kiwiberries), HYG-1426
- Penn State, Lake Erie Regional Grape Research and Extension Center — Hardy kiwi
- Environment and Climate Change Canada — Canadian Climate Normals (the frost dates in the tables, read from this site’s frost data)