Nearly everyone is familiar with the fuzzy green fleshed kiwi fruits (Actinidia deliciosa) in grocery stores. Their taste is sweet and tart at the same time. The flavor reminds me of blackberries. Best of all, kiwi vines grow well in our climate and usually aren’t damaged by winter temperatures.
There are two other types of kiwi that tolerate extremely cold temperatures. The Issai kiwi (Actinidia arguta) is extremely cold hardy, smooth skinned and self-fertile. Most kiwis require a pollinator to produce fruit. Issai kiwis are about the size of a large grape, but they may be eaten skins and all.
Another hardy type is only slightly larger than the Issai, but like commercial kiwis, plants are dioecious. One male needs to be planted for each six females in the garden or landscape. Flavor of all kiwis is similar and most have green flesh. Red, orange and yellow fleshed varieties are less common.
Flowers of all types usually appear in May and are white and quite fragrant. Aroma is similar to orange blossoms. Despite this pleasing scent, kiwi flowers are not great bee captivators.
All kiwis require some type of trellis. They have vigorous heavy vines that need support or they will sprawl everywhere. Any type of sturdy posts with heavy gauge wire works well. Vines also make an effective privacy screen.
Regardless of the kiwi type, don’t expect plants to produce fruit for about five years. Vines are usually planted between four and ten feet apart, depending on the desired use. Best fruit yields are usually obtained with wider spacing.
Kiwis should be planted in direct sun for best fruit yields. When grown in shady spots they eventually lose vigor and die out. Soil should also be well drained. Wet soil inhibits root growth. Plants also should not be fertilized too much at one time. They do respond to relatively high rates over the course of a season.
Kiwi vines require a lot of pruning. Most of the time, this is done in winter when plants are dormant. Occasionally plants can be kept under control during the growing season by minor trimming. This is especially useful for ornamental use where a stray branch can be unsightly.
One disadvantage with growing these plants is that they must be pruned regularly. Neglecting to prune them is even more problematic than not pruning grapes enough. Kiwi vines will sometimes wrap around each other. Branches will crisscross. Both of these scenarios are bad and will require major pruning. The good thing is that plants bounce back well.
Another problem, especially with the extremely hardy types is that if fruits are not harvested the vines could become invasive. Vines that spread to the wild can climb and damage trees. If no trees are available they will run along the ground until they encounter something they can climb on.
Kiwis have few insect or disease problems other than root knot nematode. Mulch is helpful to control weeds while plants are young. Once established these tough vines usually hold their own.
Ted Manzer teaches agriculture at Northeastern High School (firstname.lastname@example.org).