You planted a hardy kiwi (Actinidia arguta, zone 4b) or an arctic kiwi (Actinidia kolomikta, zone 3) a few years ago, and it hasn’t yet produced any fruit. Then you discovered you actually had to plant at least two kiwis, one male and one female, because the plant is dioecious (male and female flowers appear on separate plants). So you want to plant a spouse for your lonely kiwi, but you can’t find the label that (hopefully) indicated the plant’s sex. How can you tell if your kiwi is a male or a female?
You have to wait until it blooms. It’s really only by looking closely at the flower when it blooms in June—in fact, actually touching it!—that you can tell the two apart. Here’s what to look for:
The male flower is filled with thin stamens topped in yellow pollen. When you touch them, yellow pollen sticks to your finger.
The female flower produces flowers with peripheral stamens, but they’re sterile and don’t produce pollen. In the center, however, you’ll see white stigmas that project outward beyond the stamens and they’ll feel sticky to the touch.
There you go! Simple, isn’t it? But do have to check while the plant is in bloom.
Leaf Color Can (Sometimes) Help
You can sometimes make a good guess about the sex of an arctic kiwi (A. kolomikta) by studying its leaf color. The most commonly sold cultivar, A. kolomikta ‘Arctic Beauty’, offers foliage heavily variegated white and pink … and it’s a male. You can therefore assume that if your kiwi is very colorful, it’s probably a male. However … female cultivars of A. kolomikta too are usually variegated to varying degrees and other male cultivars may be entirely green or only slightly variegated, so the color of the foliage is more an indication of plant’s sex than a proof.
Still No Fruit
You did plant at least one male and female, but it’s been years and there are no fruits yet. What’s going wrong?
Nothing, probably! Normally, hardy kiwis and Arctic kiwis are very cold-tolerant climbing plants that produce a lot of fruit, at least, when you have at least one male plant to pollinate up to 8 females. And they’re very adaptable when it comes to growing conditions: you could say, without too much exaggeration, that they’ll grow anywhere! Indeed, they thrive in just about any well-drained soil in both sun and shade.
So why then is it taking yours so long to produce fruit?
Here are a few possible reasons:
- It’s too young
If you want to grow kiwis, you have to be very patient. Most won’t even start to flower until they’re about 3 years old and even then, rarely bear fruit in any quantity until they’re 5 to 7 or even 9 years old.
- It’s not hardy enough
Any kiwi grown in a colder zone than one for which it is recommended will likely never bloom as it flowers from new growth appearing from the previous year’s branches and if they are damaged or killed back by a cold winter, there’ll be no fruit. Therefore you have to plant your kiwi in a hardiness zone to which it is adapted.
The kiwifruit of our supermarkets, with its large hairy fruit, is called A. deliciosa (formerly A. chinensis) and it’s not hardy in cold climates. It grows best in hardiness zones 8 to 9, although it can sometimes succeed in zone 7. In the north, it will only fruit successfully a greenhouse.
The plant usually called hardy kiwi (A. arguta) is indeed quite hardy: usually to zone 4. Despite its hardiness, it’s not the best choice for regions with short summers, as the fruits take about 150 days to mature. Its fruits are small, green and smooth. There’s no need to peel them, just pop them in your mouth, like a grape!
Arctic kiwifruit (A. kolmikta) isn’t really from the Arctic, but it is the hardiest variety (to zone 3) and the best choice for northern gardeners. Its fruit ripens early as well, usually at the end of August or early in September. Its fruits are much like those of the previous species: small, green and smooth. Often, but not always, its foliage is variegated with white or white and pink, making this the most attractive kiwi.
- It’s a naturally poor producer
Curiously, the best-selling hardy kiwi by far is also the least likely to bear fruit!
The Japanese cultivar ‘Issai’, although sold as a hardy kiwi (A. arguta), is actually a less-hardy hybrid (A. arguta x A. rufa). It’s inevitably offered as the variety of choice for gardeners who don’t have enough space for two kiwi plants, a male and a female, because it’s said to be bisexual. (In fact, ‘Issai’ is 100% female, but is parthenocarpic: it can produce a limited number of fruits without pollination.) It is also said to begin to produce fruits at an exceptionally young age: only 2 or 3 years and is naturally a fairly small, weak grower, taking up less space than other kiwis.
All that sounds good, but it rarely lives up to its hype. While it may produce fruits without a male variety nearby for pollination, expect only a few fruits per plant per year… and expect none at all in colder regions. Although the stems may be hardy to zone 4b, it rarely blooms at all anywhere north of zone 6b and is only likely to be very productive in zone 7 or above. It can be very productive in mild climates, but only in the presence of a male hardy kiwi (A. arguta).
- The parent plants aren’t of the same species
When you plant a male kiwi and one or more female kiwis, they must be of the same species. In other words, a male arctic kiwi (A. kolomikta) will, under normal circumstances, only pollinate a female arctic kiwi and a male hardy kiwi (A. arguta) can effectively pollinate only a female hardy kiwi. If your male belongs to one species and the female, to another, you aren’t going to get fruit!
- There’s a lack of pollinators in the area
Usually, bees pollinate kiwi flowers but not necessarily honeybees (Apis mellifera). Kiwi flowers don’t produce enough nectar for their taste, plus they prefer to visit flowers exposed to the sun, while kiwi flowers are hidden among the plant’s foliage. Bumble bees (Bombus spp.), larger hairy bees, are much more effective pollinators. In fact, kiwifruit farmers are increasingly using commercially-raised bumblebees as pollinators. Where bumble bees are absent, you may have to pollinate your kiwis manually.
- A late frost killed the flower buds
This happens when there is a severe frost while the plant is in bud or in flower. Curiously, there is a greater risk of frost damaging kiwi flowers in a mild climate, as plant growth starts up earlier there, even while a risk of frost lingers, than in cold regions, where flowering is naturally delayed until all danger of frost is usually over.
Essentially, hardy kiwis are very easy to grow, but you have to choose the right varieties, plant at least one of each sex of the right species and be very, very patient!