How Many Blueberry Plants Are Needed for Self Pollination?

When selecting blueberry bushes (Vaccinium spp.) for the home orchard, available space is the first consideration. Although most blueberry bushes can self-pollinate, only a few blueberry species bear prolifically without a companion plant of a different cultivar for cross-pollination. With cross-pollination, blueberry bushes of all species produce larger and more abundant fruit. So, if space is available, plant at least two bushes, selecting different cultivars, and space them about 5 feet apart.

When a single bush is desired, Vaccinium corymbosum 'Sweetheart' or Vaccinium angustifolium 'Tophat' provide a reasonable size fruit crop without companion planting. 'Sweetheart' grows in U.S. Department of Agriculture plant hardiness zones 4 through 8 and reaches a height of 5 to 6 feet with a 3- to 4-foot spread in full sun or light shade. A special feature of 'Sweetheart' is double-cropping, as this hybrid produces fruit in May or June, and a lighter crop in August. 'Tophat' grows in USDA zones 3 through 7, reaching a height of 16 to 24 inches tall in full sun. Its small size makes it suitable for container planting.

Highbush blueberries (Vaccinium corymbosum) grow in USDA zones 4 through 10, depending on cultivar, in full sun. They should be selected according to zone as well as bloom period -- for effective cross pollination, blooms on the two cultivars you select must appear at the same time.

Early-blooming 'Duke' and 'Earliblue' grow in USDA zones 4 through 7. 'Patriot' produces quarter-size fruit in USDA zones 3 through 7.

Early to mid-season 'Misty Blue' and 'Sunshine Blue' grow in USDA zones 5 through 10.

Late season 'Berkeley' and 'Coville' grow in USDA zones 5 through 8.

Many states restrict shipment of certain blueberry species. When ordering, please check your state for restrictions.

Pollination requirements of blueberries go beyond cross-pollination because of the shape of the blueberry blossom. Blueberries need "buzz pollination" by bees. Unlike plants with light, wind-dispersed pollen, blueberry bushes have heavy pollen that requires insects to move it from flower to flower. Bees that buzz are the only insects that can effectively pollinate blueberries. All blueberry flowers have both male and female parts, and it is up to bees to move the pollen from the anthers to the stigma. By grasping flower stamens and vibrating flight muscles, bumblebees and other native, nonsocial bees shake pollen loose from the anthers of the drooping, urn-shaped flowers. Honeybees are less effective pollinators, as they do not buzz. Instead, they must drum on the anthers to loosen pollen grains.

Self-fertile blueberry bushes, such as 'Sweetheart' and 'Tophat,' still require pollination. Encourage bee populations to do this important job by providing flowering plants for nectar sources both before and after the blueberry bloom period.

Some growers attempt to hand pollinate plants by using a small artist's paintbrush to transfer pollen from one flower to another. However, this process is time-consuming and unreliable with blueberry bushes due to the shape and multitude of blueberry flowers. Anthers produce pollen, which has to pass through a pair of pores at the tip of each anther. Without vibration, it is difficult to collect enough pollen to successfully pollinate the flowers. Furthermore, each individual flower cluster can have as many as 16 flowers. Given the difficulty of the task of hand-pollinating, encouraging bees to your garden by planting many different types of nectar-producing plants seems a better alternative.