How Does Kiwi Fruit Grow?

Kiwi fruit, or kiwifruit (Actinidia spp.), is classified botanically as a berry. Its blended taste resembles a surprising mixture of strawberry, banana, pineapple and melon. The fruit grows almost exclusively on female vines that depend on male vines to pollinate the flowers.

The Pacific Northwest Extension Service lists three primary kiwi species as the most popularly cultivated out of more than 50 that populate U.S. Department of Agriculture plant hardiness zones 3 through 10. The recognizable brown fuzzy fruits, appropriately called fuzzy kiwi (Actinidia deliciosa), grow in USDA zones 8 through 9. Hardy kiwi (Actinidia arguta) produces smaller, non-fuzzy fruits and grows in USDA zones 3 through 8, and Kolomikta kiwi (Actinidia kolomikta), also called variegated kiwi vine, grows in USDA zones 4 through 8. Although their cold hardiness varies, all kiwi plants grow and reproduce similarly.

Kiwi fruit grows only on female vines. All kiwi vines produce flowers, but each vine bears either male or female blossoms. Although the male vines have more flowers, which produce the pollen, the female vines have larger flowers to receive the pollen. Because the male vines produce so many pollen-bearing flowers, only one male plant is required for up to eight female plants to ensure pollination. After female flowers are pollinated successfully, the fruit begins to form. The fruit reaches its mature size in summer, but it doesn’t ripen until fall. The fruit may be oblong or round, fuzzy or smooth-skinned, and the flesh colors are in shades of green, orange and yellow, depending on species.

Kiwi grows best in full sun to light shade in well-draining soil. If the roots remain in standing water for more than three days, a plant’s health is severely compromised. During hot weather, a mature kiwi vine may need up to 25 gallons of water per day. Water plants when the soil feels dry, or if the plants begin to wilt. Add enough water to wet the top 6 to 10 inches of soil, without causing the soil to become waterlogged.

For optimal fruit production, begin fertilizing kiwi vines the second year after transplanting them. Use 5 ounces of 10-20-10 or 13-13-13 fertilizer per plant. Every year thereafter, apply 1 ounce of 0-46-0, 11 ounces of ammonium nitrate and 1 pound of potassium sulfate per plant. Apply the fertilizer in two applications, with equal parts of nitrogen and potassium given once after bud break in spring and again after the flowers appear. If needed, after bud break, add dolomitic limestone to maintain a soil pH between 5.0 and 6.5.

Kiwi plants are vigorous growers. Because the vines may grow to 30 feet, space plants 20 feet apart in rows that are 16 feet apart. Plant the vines at the base of pergolas or centered between 8-foot-long T-bar supports, spaced 20 feet apart and set 2 to 3 feet into the ground. Prune plants differently, depending on whether a vine is male or female. Prune male vines once yearly -- when they finish flowering -- close to the central trunk. When the female vines set flowers, remove all the shoots that lack blossoms. In late winter when the plants are dormant, remove most of the canes that fruited the previous year, and prune the remaining canes by leaving eight buds beyond the last fruit-bearing axil. Sanitize pruning tools by letting them soak for five minutes in a mixture of 1 part household pine-oil cleaner and 3 parts water. Rinse the tools before using, and resanitize them before pruning each plant.