You Need a 'Man' to Grow Kiwi!
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Q. My son gave me a kiwi tree on Mother's Day four years ago. The salesperson said it was female and didn't need a nearby male to flower. The plant seems to be okay, but has not gotten any bigger and has never flowered. Do I need to get another plant?
- ---Denise in Morton, PA, a suburb of Philly
- ---Bob and Marika in Emerald Isle, NC
But hardy kiwi varieties (A. arguta) can be grown almost anywhere in the nation—from Zones 4 through 9. They produce large clusters of small fruits whose flavor is very similar to the big ones (kind of tropical; kind of pineapple-y) and whose skins are so thin you eat them like the grapes they resemble. (They're also incredibly rich in vitamin C.)
And the super-hardy varieties (A. kolomikta) can be grown in almost impossibly chilly regions—all the way down to Zone 3. But they're all vines. And not just "vines" but rampant vines that grow so quickly and so vigorously that our resident fruit expert Dr. Lee Reich warns they should be pruned several times a season to keep them from overwhelming the property and shading themselves into fruitlessness. (Although he adds that the super-hardy types are much less rampant than the others.)
Kiwi vines do become almost tree-like at their base over time, but a plant that appears to have the form of a tree and hasn't grown much in four years may not be a kiwi—so some questioning of the gifter and maybe a visit to the place of purchase may be helpful. It would be much less suspicious if you had said that the plant was overwhelming the place but hadn't yet bloomed, as it can take a vine five years to begin flowering—especially if it isn't being aggressively pruned.
And, although there are a few self-fruitful varieties, the vast majority of kiwi need a male plant nearby (within 35 feet or so) to pollinate the fruit-bearing females. This is so important that it's boxed and highlighted in the kiwifruit section of Lee's latest book "Grow Fruit Naturally" (Taunton Press; 2012).
The report of blossoms without fruit is a little more troubling. Once male and female vines are both flowering, there should be fruits—IF pollinators are present, and the male is compatible. (Lee explains that the male vine doesn't have to be the same exact species as the girls, but it does have to flower at the same time.) If we assume that our North Carolinians have the right kind of guy, their location could be the problem.
MapQuest reveals that 'Emerald Isle' lives up to its name—it's a long, thin strip of land about two miles East of the actual Carolina coastline, a spot that might not host an abundance of native bees. I'm thinking a beehive or hand pollination might be necessary in such an extreme (but undoubtedly breathtaking) location. Lee adds that Kiwi is also wind-pollinated to some degree, and plants should ideally be positioned so that the prevailing wind moves from the male towards the females.
Lee explains that all kiwi vines need acidic soil, perfect drainage, serious support, lots of pruning, and protection from extreme temperature swings. "Keep them away from South-facing walls and other areas that heat up in winter" he advises, "and protect young plants from winter weather as if they were fig trees their first few years of life. After that, they get pretty tough." Lee adds that one male can 'service' up to eight females, and that it can be pruned back hard after its flowers fade, as it is a true one-trick pony.
No matter which type you grow, choose the site well, read up on the plants' needs and differences, and be prepared to do a lot of pruning and to give the vines a lot of support. (All of Lee's many books on fruit growing include detailed instructions on pruning and trellis construction.) The edible reward for your labors will be great, he assures us; and he adds that the vines of the hardy and super-hardy varieties are so attractive they were first grown solely as ornamentals.
Their only real insect enemy is the Japanese beetle, so keep an eye out for those armored invaders. But keep an even sharper eye on your local cats. Lee warns that something in kiwi vines can make catnip look like alcohol-free beer to kitty, with some felines going so crazy that they pull young plants right out of the ground, roots and all.