Hardy Kiwi

A hardy kiwi vine is a long-term proposition. The first crop tends to arrive in year three or four, sometimes year five, and in the meantime the vine grows with alarming vigor — thirty feet or more in a good season. Most of the early work is structural: you build a trellis that can handle the weight of mature vines and several hundred pounds of fruit, and you prune ruthlessly to keep the plant from strangling itself. The fruit, when it finally comes, is grape-sized, smooth-skinned, and tastes unmistakably like kiwi. It is worth the wait if you have the space and the patience.

The critical mistake beginners make is planting only female vines. Hardy kiwi is dioecious — male and female flowers appear on separate plants — and a female vine without a male nearby will bloom beautifully and set no fruit at all. You need at least one male for every six to eight females, and the male must be a compatible species. Actinidia arguta is the species most commonly grown for fruit; Actinidia kolomikta is hardier still, reliably to zone 3, but produces smaller fruit and the two species will not cross-pollinate. If you plant an arguta female, you need an arguta male.

The trellis matters more than most fruit-growing guides suggest. Hardy kiwi vines are not delicate climbers; they are heavy, woody, fast-growing plants that can pull down a flimsy arbor by midsummer. A two-wire system on sturdy posts, or a pergola built for grapes, tends to work. T-bar or horizontal wire setups are common in commercial plantings. Whatever you build, anchor it well — the vines will test it.

Late frosts are the other persistent problem. Hardy kiwi leafs out early in spring, and a hard freeze after the shoots have emerged can kill the year's fruiting wood. The vines themselves are hardy to minus twenty-five or colder, but the tender new growth is not. If your garden is in a frost pocket or a zone-4 valley where late May freezes happen, consider Actinidia kolomikta instead — it leafs out a week or two later and tends to miss the worst of the late cold.

Pruning is an annual necessity. Hardy kiwi produces fruit on one-year-old wood, which means you prune after harvest to remove spent canes and thin out crowded growth. Unpruned vines become tangled masses of unproductive wood within a few seasons. The first few years, before fruiting begins, focus on establishing a framework — a main trunk and a few lateral arms trained along the wires. After that, treat it like a grape vine: cut back to the framework each winter and let new shoots grow out each spring.

Harvest comes in late September or October, depending on variety and location. The fruit ripens over a period of several weeks and does not all come ready at once. A ripe hardy kiwi is soft to the touch, like a ripe pear; if you pick them hard, they will ripen on the counter but the flavor is not as developed. The skins are edible and the fruit stores well in the refrigerator for several weeks.