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How Cranberries Grow: Pollination

Cranberry growers in southeastern Massachusetts and Cape Cod are bringing the buzz back to the cranberry bogs with migratory honey bees and bumble bees for cranberry flower pollination. It is vital that growers introduce migratory honey bees and/or bumble bees; According to Anne Averill, Entomologist with U-Mass Cranberry Station “Similar to many other fruit crops, bees are needed for adequate pollination. Cranberry flowers are not capable of self fertilization so pollinators are required to move pollen from one flower to another.” Often, several pollination visits are needed to ensure good berry development.

A grower needs to carefully time the delivery of the bees to the bogs. Cranberry blossoms are not a high priority flower for all bees. Cranberry blossom do not offer the same nectar appeal that other crops offer. If bees are introduced prematurely, the bee will fly off and find other flowers to pollinate, such as area weeds. Once a cranberry bog starts to blossom at 5%, bees should be introduced. Honey bees are hard workers, but they do prefer a dry day. Bumble bees offer another option for pollination, and will work earlier and later in the day and when the cranberry bogs are wet. It’s a grower’s choice and many growers introduce both honey and bumble bees to their farms.

Migratory honey bees will remain on the cranberry bogs until mid-July; after that, cranberry pollination has ended, and the bees will continue to forage for pollen and nectar from other flowers in the area. Once pollination is over, migratory bees relocate to another crop. The only buzz of the bee is from the native bees that live within the bog system all year long.

View a slideshow on cranberry pollination.