Kiwi, a vigorous, vining plant, can be successfully grown in Pennsylvania, but the endeavor requires careful varietal selection and an understanding of the state’s climate. The commercially familiar fuzzy kiwi (Actinidia deliciosa) cannot survive the Pennsylvania winter, having insufficient cold tolerance and requiring a longer growing season. Success relies entirely upon cultivating its hardier relative, the Hardy Kiwi or Kiwiberry, which is a much more cold-tolerant species. This fruit-bearing vine is a rewarding addition to a home garden, provided the grower addresses its specific needs for pollination, support, and annual pruning.
Identifying Kiwi Varieties Suited for Pennsylvania Climates
The distinction between the two main types of kiwi is the most important factor for growing in a temperate climate. The large, fuzzy kiwi found in grocery stores, Actinidia deliciosa, is only suitable for warmer regions, as it is damaged by temperatures below 10°F. In contrast, the Hardy Kiwi, primarily Actinidia arguta, is cold-tolerant, capable of surviving dormant winter temperatures as low as -25°F to -30°F, making it the appropriate choice for Pennsylvania’s USDA hardiness zones 5b through 7a.
Hardy Kiwi produces smaller, grape-sized fruit with smooth, edible skin, eliminating the need for peeling. While the vine itself tolerates severe cold, the new spring shoots are highly susceptible to late spring frosts, which are common across the state. Planting in a location that avoids frost pockets is therefore necessary to protect the early-emerging growth and the subsequent flowers.
Popular and suitable cultivars of Actinidia arguta for the region include the female variety ‘Ananasnaya’ (often called ‘Anna’), which is known for its sweet fruit and vigorous growth. Another commonly mentioned variety is ‘Issai,’ a self-pollinating type, though it is often less vigorous and produces smaller fruit than the standard dioecious varieties.
The Role of Pollination
Most kiwi vines are dioecious, a botanical term meaning that individual plants bear only male or only female flowers. This reproductive characteristic means that both a male and a female plant must be present for the female vine to produce fruit. The female plant carries the fruit, while the male plant’s sole function is to supply the necessary pollen.
A single male vine is typically sufficient to pollinate several female vines, with a common planting ratio being one male for every five to nine females. For successful fruit set, the male plant must be of the same species and its flowering time must synchronize with the blooming of the female plants.
When purchasing vines, it is important to ensure they are correctly labeled for sex, as they cannot be identified until they begin to flower. Although some self-fertile varieties, like ‘Issai,’ exist, even these cultivars generally yield a larger and more reliable crop when a male pollinator is planted nearby. The male vine should be planted within 50 feet of the female plants to ensure effective transfer of pollen, primarily by insects.
Preparing the Planting Site and Structure
Hardy Kiwi vines are vigorous, often growing over 20 feet in a single season, which necessitates a robust and permanent support structure installed before planting. A T-bar trellis or a sturdy pergola system is recommended to handle the substantial weight of a mature, fruit-laden vine, which can yield up to 100 pounds of fruit. The trellis should be built with durable materials and anchored securely, often reaching a height of 6 to 7 feet for ease of management.
The ideal planting site requires full sun exposure, although the vines can tolerate partial shade, with full sun promoting the best fruit production. Selecting a location that is sheltered from strong winds is also important, as wind can damage the fragile vines.
Kiwi vines thrive in deep, fertile soil that drains well, as they are susceptible to root rot in waterlogged conditions. The soil pH should be slightly acidic to neutral, ideally ranging between 5.0 and 6.5. Vines should be spaced approximately 10 to 15 feet apart to allow for their significant growth and to ensure adequate air circulation once they are trained onto the support system.
Annual Maintenance and Pruning for Fruit Production
Pruning is the important annual task for maintaining a productive kiwi vine and is divided into two distinct periods: winter and summer. The vines produce fruit exclusively on new growth that arises from one-year-old wood, making strategic pruning necessary to encourage this fruiting wood.
Dormant, or winter, pruning is performed in late winter before the sap begins to flow, typically involving the removal of 50 to 70 percent of the vine’s growth. During this time, all dead, damaged, or older canes that have already fruited are removed to redirect the plant’s energy into new growth. The permanent main trunk and two scaffold branches, called cordons, are left intact, and the one-year-old fruiting laterals are shortened.
Summer pruning involves thinning out dense, non-fruiting branches and training new growth to prevent the vine from becoming an overgrown, unproductive mass. This summer work improves light penetration and air circulation, which are important for fruit quality and disease prevention. Consistent watering is also necessary, especially during dry spells, with vines requiring about one inch of water every ten days for the first year until they become established.