Kiwi Flower Differences

Distinction

• Although there are more than 50 species of kiwifruit (Actinidia spp.), three types are most commonly cultivated. The vines that bear the recognizable brown, fuzzy market fruits (Actinidia deliciosa) grow perennially in U.S. Department of Agriculture plant hardiness zones 8 and 9; hardy kiwi (Actinidia arguta) tolerates colder temperatures in USDA zones 3 through 8; and the variegated kiwi vine (Actinidia kolomikta) grows in USDA zones 4 through 8. Regardless of species and cultivar, kiwi vines are almost exclusively male or female. One notable exception is “Blake,” a cultivar that bears male and female flowers on the same vine.

Male Flowers

• Male kiwi vines have more flowers than do female vines, but they are typically only half the size of the female blossoms. The sole function of the male flowers is to produce pollen that fertilizes the female blooms, which is what produces the fruit, so a male kiwi plant must be planted near a female vine. Male flowers produce pollen for only two to three days after they open, so the female flowers must be blooming during this pollination window for successful fertilization. Because the male vines are somewhat less hardy than the females, they are sometimes damaged by late spring frosts that may kill the flowers. If this happens, the female vines cannot bear fruit because there is no male pollen produced to fertilize them.

Female Flowers

• The female flowers have prominent central pistils, which are the structures that receive pollen from the male flowers. Wind pollination is uncommon with kiwifruit, and the flowers rely primarily on honeybees, bumblebees and native bees to transfer the pollen. The female blossoms are fragrant, but they do not produce the sweet nectar characteristic of most flowers. Female flowers can be pollinated seven to nine days after they open, even after the petals fall from the blossoms.

Pruning

• The differences in male and female kiwi flowers dictate how and when the vines need pruning for optimal flower production the following season. After the male flowers finish blooming, the male vines benefit from hard pruning during the active growing season so only one-third of the plant remains. This forces new growth for the following season that produces lots of flowers to pollinate the female vines. The male vines should not be pruned during the dormant season. Female vines benefit from pruning during the growing season as well as the dormant season. During periods of active growth, overgrown female vines benefit from thinning so the sunlight can penetrate the lush foliage and reach the fruiting wood. During the dormant season, the shoots that produced fruit the previous year should be removed so new growth can flourish to produce the next-season flowers.