Question: A client called the plant clinic this week and asked if she could grow kiwifruit in our area?
Answer: Growing kiwifruit in the warmer areas of the Pacific Northwest can be easy, fun, rewarding and perhaps the most exciting gardening adventure that you will ever try, as long as you plan ahead and do the routine plant maintenance required each year. Kiwifruit is native to Southeast Asia, and there are more than 50 species. The term “kiwifruit” is somewhat of a misnomer because they are actually berries, and were known as “Chinese Gooseberries” until 1959. The most common kiwifruit species is actinidia deliciosa cultivar Hayward, the fuzzy kiwifruit we are all familiar with. This species, however, is not extremely cold-hardy and may suffer cold injury some years in the Pacific Northwest. Cold damage usually occurs when temperatures drop during the night after a warm spell, particularly in the fall. Generally the fruit is large with green skin covered with brown fuzz. This cultivar is recommended only for areas of Oregon with mild winters. The harvest can be as late as October or November. Hardy kiwifruit, also called kiwi berries because of the smaller size, are better adapted to our region because they are very cold hardy and the fruit can be harvested in September. Of the hardy kiwifruit, the easiest to find are actinidia arguta cultivar ‘Ananasnaya’ (sometimes called ‘Anna’). This species has jade colored skin, bright green flesh, black seeds and a pineapple-like flavor. The plants are very vigorous and produce good-quality, highly aromatic fruit.
Members of the actinidia family are generally dioecious (male and female flowers grow on separate vines). Only the female vines will produce fruit. Pollen from the male flowers is required to fertilize the female flowers. About one male is needed for every eight female plants. Kiwifruit flowers are pollinated mainly by honeybees, although wind may play a minor role.
Proper site selection, soil preparation, irrigation availability and vine training are essential considerations for successful vine development. Choose a site in the warmest area of your garden, avoiding low areas subject to frost. Avoid windy areas. Kiwifruit vines do best in deep, well-drained soils. Avoid any areas with standing water in the winter. The soil pH is best between 5 and 6. Ample water is crucial for proper fruit development. Water your newly planted vines thoroughly about twice a week during the dry season. Do not overwater. Fertilize your vines using a well balanced fertilizer, a couple of times during the spring. Kiwi fruit vines will climb on anything they can wrap around. An arbor, trellis, and espalier support along a fence or wall are all possibilities. The stronger, the better since the vines can grow up to 15 feet wide. Whatever type of structure you use, it should be in place the same season you plant your vines. Proper pruning during the establishment years is necessary to establish a well-formed permanent framework for the vine. Prune dormant kiwi vines in late December to late January. Kiwifruit produces a crop on shoots that grow from 1 year old canes (last year’s growth).
It is better to plant self-rooted vines rather than grafted vines. Severe cold spells can kill a grafted vine. It is recommended to plant 2-year-old bare-root or container stock. Don’t allow the roots to dry out. Plant your vines as early in the spring as possible. Make the planting hole large enough to accommodate the roots without bending them. Do not apply fertilizer directly into the planting hole as this could injure the plant. Plant your vines just deep enough to cover the roots, taking care not to mound the soil around the plant. Plant vines about 10 feet apart.
In the warmer regions of Oregon, fuzzy kiwifruit is harvested in October and November when the fruit is still hard and the seeds are black. The fruit can be stored in a cold area for several months and is ripened as needed by leaving out in a warm spot for a few days. Hardy kiwifruits can be harvested beginning in September, when the fruits are soft to the touch. These should be eaten right away, or frozen for later enjoyment.
You can acquire Kiwifruit plants from local nurseries or from online sources. With a little planning, you can amaze your friends with this unusual fruit.
Do you have a gardening question? Please email, call, or visit the Douglas County Master Gardener Plant Clinic at firstname.lastname@example.org, 541-672-4461, or 1134 S.E. Douglas Ave., Roseburg.