The fruit commonly known as kiwi, or kiwifruit, is produced on a vigorous, woody vine. The species most widely grown for its familiar brown, fuzzy fruit is Actinidia deliciosa. The plant is a perennial that can live for fifty years or more, providing fruit for decades once it reaches maturity. As a climbing plant, it requires support to grow upright and produce fruit effectively.
The Kiwi Plant’s Structure
The kiwi plant is classified as a liana, a woody vine that climbs up other objects or trees in its native habitat. Its stems develop into thick, rough, woody canes that can grow rapidly, sometimes reaching 6 to 12 feet in a single season. The leaves of the most common varieties are large, round, and slightly heart-shaped, often having a soft, fuzzy texture on the underside.
New fruit develops from small, whitish or pale yellow flowers that bloom in late spring or early summer. These flowers are borne on the shoots that grow from the one-year-old canes, meaning the previous season’s growth determines the current year’s fruit production. Female flowers are identifiable by their prominent, multi-branched central pistil, which develops into the fruit after successful pollination. The fruit is botanically a berry that ripens in the late autumn.
Cultivation Needs and Support Systems
Because the kiwi vine is a vigorous climber, a robust support system is necessary for managing its size and weight, especially when grown commercially. Growers commonly use structures such as T-bar trellises or pergolas to train the vines and keep the canopy open. These systems help to optimize the vine’s exposure to sunlight, which is necessary for fruit development and proper ripening. The fruit-bearing canes are typically tied horizontally to wires strung across the support structure.
The kiwi vine is dioecious, meaning individual plants have either male or female flowers. Female plants produce the fruit, while male plants produce the pollen needed for fertilization. For successful fruit production, growers must interplant female vines with a male pollinator, often at a ratio of about one male plant for every six to ten female plants. The male and female vines must be of the same species and flower simultaneously to ensure proper cross-pollination.
Where Kiwis Originated and Where They Thrive
The kiwi plant originated in the Yangtze River Valley of China, where it was historically known as the Chinese gooseberry. It was not until the early 20th century that the plant was introduced to other parts of the world, including New Zealand, which eventually gave the fruit its modern name. The global commercial success of the fruit, particularly the ‘Hayward’ variety, established new production centers outside of Asia.
Kiwifruit thrives best in temperate zones that provide a long, frost-free growing season of 225 to 240 days. The vines require a specific period of winter cold, known as chilling hours, which is necessary to break dormancy and ensure abundant flowering in the spring. For example, the common Actinidia deliciosa cultivar often requires 600 to 850 hours of temperatures at or below 44 degrees Fahrenheit (7 degrees Celsius). Today, major producers include New Zealand, Italy, China, Chile, and Greece, all of which offer the climate conditions necessary for this vigorous vine to flourish.