Kiwi Growing Guide
Varieties
There are three types of Kiwis we can grow for fruit in the US. Fuzzy Kiwi (Actinidia deliciosa), is the species that produces the brown fuzzy Kiwi we commonly find in stores. It is a very vigorous vine that is hardy to about 0°F. Hardy Kiwi (Actinidia arguta) produces smaller, very sweet and flavorful fruit that has a smooth skin and can be eaten just like grapes. It is also a very vigorous vine and, depending on the variety, is hardy to minus 25°F or below. Both Fuzzy and Hardy Kiwi like a site with at least 1/2 day sun. Arctic Beauty (Actinidia kolomikta) is a more compact vine that also produces smaller, but very flavorful fruit with smooth skin.
Site Selection – All Kiwis like well-drained soil, from clayey to sandy. Fuzzy and Hardy Kiwi like 1/2 day to full sun. Arctic Beauty Kiwi likes a site with some shade and is very happy on a partially shaded arbor or on the north side of a wall or fence. If your soil is very wet, you can make a mound of soil several inches above the soil surface. This will allow water to drain away from the roots.
Support – All kiwis are twining vines. Because of their vigor and heavy crops, Fuzzy and Hardy Kiwi need a strong arbor, trellis or other support. A typical arbor for these species would be 12 feet long, 6 feet wide and 6 feet tall. Use 4×6 or larger, pressure treated posts and 4×4, 2×6 or larger cross arms for your arbor. Hi-tensile, New Zealand style fence wire works well spaced 1 1/2 to 2 feet apart across the cross arms. Arctic Beauty Kiwi is less vigorous and bears less fruit so it can be grown on a fence, wall, garden trellis, or other such support.
Planting Your Kiwis
1. Prepare your plant – If you are planting a bare-root plant, inspect the roots and cut off any broken or overly long ones. If you are planting a container plant, remove the pot and loosen the root system. If it is very dense, you may have to lay the plant on the ground and press hard on the root ball with the palm of your hand. Pull some roots out of the root ball and, if they are very long, trim them back
2. Prepare the site – If your planting site is covered by grass, start by removing a thin layer of sod in a circle 2-3 ft. in diameter. Removing it is important as grass will compete with your new plants for water and nutrients. In this newly cleared area, dig a hole wide and deep enough for the roots. After digging the hole, rough up the sides with your shovel so that your plants roots can easily spread.
3. Planting – For bare-root plants, locate the soil line on the trunk. This is indicated by a change in color, often from a dark green to yellow or black. Be sure that this point is no lower than the soil level surrounding your planting hole. For container plants, it is very important that the soil line of the plant in the pot is the no lower than the soil line surrounding the planting hole. Planting too deep can kill Kiwis. Make sure the roots are spread out in the planting hole and fill the hole with the soil you took from it. Work the soil around the roots and when the hole is full, tamp down the soil and water your plant in well. Please note We advise you to fill the planting hole with the soil that came from it. We do not recommend adding amendments or other materials to this soil. To be strong and vigorous, the roots of your Kiwi will need to grow far and wide into the surrounding soil. Once your new plant is in the ground, you can spread compost, organic fertilizer and other materials on the soil surface to feed the plant naturally.
Fertilizing and Irrigation – Because of their vigor and rapid growth rate, Fuzzy and Hardy Kiwis can use abundant amounts of nitrogen. After the first year, applying 1/2 lb. of nitrogen annually in early spring will ensure good growth throughout the summer. We recommend using organic sources of nitrogen. For example, if an organic fertilizer contains 5% nitrogen, apply 10 lbs. per plant. After 4-5 years, increase the nitrogen to 1 lb. annually. Arctic Beauty Kiwis also benefit from annual fertilizer applications, but because of their lower vigor, they should need no more than 1/2 as much as the Fuzzy and Hardy Kiwis. All Kiwis have a shallow, spreading root system and need adequate water during the growing season. A 4-6″ deep mulch in a 2-3 ft. circle around the plants will conserve moisture and deter weeds. Hay, straw or compost are good materials for mulching. During warm weather, a deep watering once a week should be sufficient. Be sure to check the soil and be careful not to overwater your plants. Reduce watering frequency in early fall to harden off your plant for winter weather.
Pruning and Training – After planting, tie your plant loosely to a stake or other support to hold it up. Once roots are established and growth begins, your Kiwi will likely produce one or more vigorous shoots from near the base of the plant. After these shoots grow approximately 2 feet, tie the strongest to a stake and allow it to grow to the top of your trellis. Tip back the other shoots at this time so they won’t compete with one you have chosen. After the main shoot reaches the top of your trellis or support you can remove the other less vigorous shoots, leaving the one you have chosen to become the main trunk of your Kiwi vine. After the main shoot grows past the top of your trellis, cut back the tip and allow two upper buds to grow. Train these new shoots to grow along the wires or structure of your arbor or trellis and tie them loosely. These new shoots will form the lateral cordons and become the permanent structure of your Kiwi.
By the end of the second season, you should have a good framework established for your Kiwis. During the second winter, prune back the new cordons (side shoots) to 10-12 buds. The lateral shoots from these basal buds will produce shoots, which can bear your first flowers and fruit. Train one of these shoots along the trellis or arbor to add length to the cordon and repeat the pruning process the following winter. Continue this process until the cordons reach the limit of your support.
Kiwis flower and bear fruit on shoots that have grown from the previous season’s growth. Annual pruning during the dormant season is important for good fruit production. Pruning is best carried out in December or January and consists of heading back the previous year’s new shoots to 10-12 buds and removing older wood, if any, that has already fruited. In addition, twisted, tangled and broken shoots should be removed as well as those crossing from one side of the plant to the other. Any shoots hanging to the ground should be removed or tied to the support. As you prune and observe your Kiwis, you will get a sense of what should stay and what should be removed.
Male plants are grown and pruned in the same way as female plants, but, since they are grown only for their flowers they need only about 1/4 of the trellis space and can be pruned more severely.
Please note that it may take 3-4 years or more before Fuzzy and Hardy Kiwis begin flowering and fruiting.
Spring Frost Protection – Depending on the species, Kiwis can withstand temperatures from 0°F to minus 40°F. While the plants are hardy to these temperatures, the new shoots and flowers of all Kiwis can be damaged by temperatures below approx. 31°F. If plants have begun growth and frost threatens, a simple way to prevent damage is to sprinkle your plants during the night with water. While ice will form on the plant, the temperature of foliage will not fall below 32°F. If the plant is small, you can simply cover it with plastic or fabric.
Winter Care of the Fuzzy Kiwi – While the Fuzzy Kiwi is hardy to 0°F., sunny weather while nighttime temperatures fall below 20°F can cause sap to flow which can freeze and damage the trunk. In severe cases, this may result in girdling of the trunk and death of the top. While shoots may come from the base, the top of the plant is lost. The best way to prevent this damage is to wrap the lower 2 to 3 ft. of the trunk with some kind of insulating or reflective material. Painting the trunk with a 50/50 mix of water and white, interior latex paint can also help prevent this damage. In addition, mulching the base of the plant with straw or other material will also help protect your Fuzzy Kiwi during severe winter weather.