Cultivate kiwi

If you come by Hildegard Hendrickson’s yard while the kiwi vines are in bloom, you might find her on a ladder, at age 75.

She and her husband built the supports too high when they planted her first vines in 1980 at their North Seattle home, but Hendrickson learned to make do.

Now she’s a renowned regional authority and popular guest speaker, although she says Bob “Kiwibob” Glanzman is the real expert. Still, Hendrickson’s vines produced 1,000 fruits last year.

That gets back to why you’ll find her on a ladder.

“I still hand-pollinate,” says Hendrickson. “I pick a male flower and touch it to five females. It goes very fast and I get more and bigger fruit than people who depend on bees.”

Kiwis produce both male and female flowers on separate vines. In order to get fruit, both must be present and blooming simultaneously. The pollen produced by the male flowers stays viable for only two to three days, but one male can pollinate up to eight females, especially with Hendrickson as a matchmaker.

The botanical name for kiwi is Actinidia, a genus native to Asia including over 50 species of deciduous vines. The fuzzy brown kiwis at the supermarket are usually Hayward, an Actinidia deliciosa cultivar (sometimes referred to as A. chinensis), readily available, and hardy to 10 degrees Fahrenheit.

However, vines can take up to eight years to bear fruit and up to eight more to reach maximum production of as much as 100 pounds per vine.

“Be patient,” says Hendrickson. The reward is a delicious crop with a flavor hinting of melon, strawberry and banana all in one. Fuzzy kiwis, when picked after the first frost and before ripening, last through months of storage under the right conditions. Take some out as needed to ripen on the kitchen counter or in a brown paper bag.

Hendrickson eats two per day from late fall into June.

“I harvest the day after Thanksgiving,” she says, “Then I put each fruit in a fold-top plastic sandwich bag that keeps in moisture so they stay plump. I make a single layer in a cardboard box, cover them with newspaper and repeat, with no more than two single layers per box. Store them in a cool ventilated area where they won’t freeze.”

FOR QUICKER GRATIFICATION

Less patient gardeners might try two other species, both cold hardy. One called A. arguta, or “hardy kiwi” tolerates minus-25 degrees F, and the species A. kolomikta, (sometimes sold as Arctic Beauty), survives to minus-40 degrees. Both produce fruit smaller than Hayward, with smooth, edible skin. They should be ripened on the vine.

Scott Gruber, owner of Calendula Nursery in Tacoma recommends always having both male and female plants if you want fruit. “The hardy kiwi variety Issai is consistently sold as being self-fertile,” says Gruber. “While this is technically true, without a male pollinator the average person may not see more than a couple of fruits for several years.”

Gruber appreciates A. kolomikta for its ornamental qualities plus fruit. He says, “The male is the flashier of the two and contributes a delightful splash of color to the garden wall or fence with its leaves variegated in green, pink and white. Unlike fuzzy and hardy kiwis, Arctic kiwis appreciate a bit of shade. Combine that with their less aggressive growth and smaller habit and you have a fantastic climber for a deck or patio pot.”

GETTING OFF TO A GOOD START

Kiwi vines grow vigorously and need careful tending the first few years to establish vines well-formed for maximum fruiting and convenience. They should be at a height that can be reached without standing on a ladder. Follow that with regular pruning for size control and more fruit.

“I prune twice a year,” says Hendrickson. “I prune in winter when the vines are dormant, before Jan. 15. If you do it later when things warm up and the sap is running, it will bleed out. I prune again in the summer after the blooming and pollination.”

Kiwis need support. Glanzman, or “Kiwibob” as he’s known regionally, recommends steel pipe set in concrete and a “box” trellis, an inverted “U” with cross members. If made of wood, use treated four-by-fours. Other options include arbors, pergolas, espaliers and “T” bars with wire. He says, “Whatever structure you use should be in place at planting time.” He suggests planting vines about 10 feet apart in rich, well-drained soil.

He and Hendrickson team up to speak publicly about the joys of growing kiwis.

“The first thing I tell people,” Hendrickson says, “is that they aren’t tropical and don’t need hot weather.” Glanzman gets scientific. He considers himself the straight man and Hendrickson the entertainer, but he does have a good kiwi story.

When a man asked how to tell if he had both male and female vines, his wife said, “Put two pots in a room and if they start to argue, you know you have a pair.”

Kiwibob’s Training and Pruning Basics

Advice from Bob “Kiwibob” Glanzman, a regional expert in growing kiwi.

First Season: Develop a single permanent trunk. Growth should reach the top of the trellis, a comfortable height for working while standing on the ground. If not, “cut back to three or four buds and start over,” he advises.

Second Season: Develop permanent main cordons. These two side branches of the vine, trained perpendicular to the trunk, produce fruiting laterals. “Don’t allow cordons to wrap around the center support wire more than three times,” he says.

Third Season: Develop well-spaced fruiting laterals. “Have laterals about 18 inches apart on opposite sides of the cordons, 36 inches apart on the same side of the cordon.”

Fourth Season: You should now have the basic structure completed.

Fifth Season and Beyond: Maintain your vines. “After two or three years, laterals are done being useful. Prune them out. Let new ones grow from the cordon at the bases of old laterals,” he says.

Candace Brown, for the News Tribune

This story was originally published May 16, 2009 at 12:00 AM with the headline "Cultivate kiwi."