Written by Laura Marrinan, University of Minnesota student
HORT 1003 Horticulture for the Home Garden, Spring 2014
Kiwi is a tasty treat that is typically thought of as a tropical or warm climate fruit. However, Minnesota gardeners can get in on the action as well. The practice of growing kiwi in Minnesota has been around since University of Minnesota's Professor Samuel Green began growing cold-hardy varieties in 1892.
According to Drs. James Luby and Emily Hoover from the University of Minnesota's Department of Horticultural Science, kiwifruit in Minnesota needs to be one of the following species: Actindia kolomikta 'Arctic Beauty', A. arguta 'Bower Berry', or A. polygama 'Silver Vine' (2). These cold hardy kiwifruits don't look like the fruits you typically pick up at the grocery store. They are hairless, skinless and generally have a much higher sugar content. These fruits are also usually about the size of a grape. A. kolomikta can be grown successfully in most areas of Minnesota because it can survive in USDA Hardiness Zone 3, while A. arguta and A. polygama, both are most successful in the central and southern part of the state, USDA Plant Hardiness Zone 4 (2).
Starting your kiwifruit
Kiwi vines can be found at many retail nurseries during the growing season, according to Luby and Hoover. To produce fruit, one male plant is needed for every six female plants. The female plants produce the berries while the male plants are the source of pollen. To differentiate the plant sexes look for at the structure of the plant and the size. The female blossoms have a center pistil to receive the pollen and are usually twice as large, according to an article by horticulturist Victoria Lee Blackstone (1). The male plant will also typically have much larger flowers than the female. Depending on your location, some varietals will be more successful than others (see chart). A. kolomikta is the top performer throughout Minnesota because of its hardiness. This is also a variety that will taste fairly similar to commercially available kiwi (2).
According to Luby and Hoover, there are multiple components to consider when starting your own kiwifruit vines. The ground must be fairly sloped and shaded from the afternoon sun. This will help keep the fruit in a moist, cool soil that is preferred by the vines. To help retain moisture, the soil can be covered with wood chips, leaves, or pine needles. This can also help control weeds, retain a consistent temperature and promote healthy roots. Although the soil needs to retain moisture, it is also important to choose a site that is well-drained and porosity (2).
The soil should have a pH of neutral to slightly acidic, around 5.5-7.5 (2). U of M Soil Test Lab Kiwifruit will also benefit from a fertilizer containing nitrogen and the chloride form of potassium. The recommended analysis of fertilizer for kiwifruit is 33-0-0, or 33% nitrogen, 0 % available phosphate and 0% soluble potash. This fertilizer should be applied from spring until early July.
Kiwi vines require support. They grow upward in a counter-clockwise direction, so using a pole or trellis will help direct the growth (4). Fencing will also help the vines grow in the proper direction and provide support.
Protecting kiwifruit during Minnesota winters is important. The onset of winter comes with two major issues for these vines: animals and weather protection. In Minnesota, cottontail rabbits can cause extensive damage to plants when they are looking for food in early winter. Fencing your vines will help prevent hungry rabbits from damaging your plants (2). Rabbits and Trees and Shrubs
Proper shading of the plants is important because of all the direct sunlight and the sun reflected off of the snow. Slipping a burlap sack or spiral wrap over the trunks will help protect your vines from sunscald (4).
(1) Blackstone, V.() Differences Between Male & Female Kiwi Vines. SF Gate. http://homeguides.sfgate.com/differences-between-male-female-kiwi-vines-45054.html
(2) Luby, J., & Emily, H. (2010, September 10). Plant and Site Selection. Commercial Fruit Production in Minnesota. Retrieved May 4, 2014, from http://fruit.cfans.umn.edu/kiwifruit/selection/
(3) Kiwifruit Berries. (n.d.). Commercial Fruit Production in Minnesota. Retrieved May 4, 2014, from http://fruit.cfans.umn.edu/kiwifruit/selection/
(4) McKenzie, J., & Emily, H. (2007). Hardy Kiwifruit in Minnesota Gardens. Commercial Fruit Production in Minnesota. Retrieved May 4, 2014, from http://fruit.cfans.umn.edu/?s=kiwi
(5) Trunk Wraps. (n.d.). Commercial Fruit Production in Minnesota. Retrieved May 4, 2014, from http://fruit.cfans.umn.edu/kiwifruit/irrigation_fert_harvest/