Pollinators, start your engines!

I am hoping for a bounteous blueberry crop this year. Though only time will tell, we can get a hint as to what is to come by looking at the spring flowers that the blueberry bushes have started to produce.

The earliest blueberry blossoms have begun to flower, and leaf-out is just beginning too. Look for the ruddy-peeling bark of the highbush blueberry for confirmation, though we also have three other Island varieties, including lowbush blueberries.

The flowers are quite identifiable. White, pink, red or even greenish tinged clusters of bell-shaped flowers provide premonition of future fruit. Though these plants have the ability to self-fertilize, it is unlikely to happen that way.

Blueberries resist self-fertilization through a variety of means. For fertilization to occur, pollen produced by the anthers must reach the stigma to fertilize the ovule. One blueberry flower’s anthers and stamens (male parts) are shorter than their style (female part), so pollen from one plant cannot get into the same plant’s stigma to fertilize itself. 

More often than not, it takes at least two blueberry plants to tango, in order for fertilization to take place. To be fruitful (and multiply) a blueberry plant couple cannot do it alone. The matchmakers in these relationships are furry fliers — bees and other pollinators that make berries possible.

The pollen of blueberry plants is thick and heavy. It cannot move on its own, nor can wind provide the mode of transport for pollen. Insects are necessary for blueberries to fruit.

The most common pollinators of blueberries are bees. Indigenous bees, including bumblebees, solitary bees, mason bees and leaf-cutting bees, perform the work of bringing pollen from one blueberry plant to another. So do nonnative bees, such as honeybees, though they are known to be less efficient than the natives because of their shorter mouthparts. These bees are attracted to blueberry flowers due to their odor and sweet nectar that they use for food.

Other not-so-helpful bees are also engaged by the luscious blueberry flowers. Robber bees, such as carpenter bees, steal nectar by making a hole in the base of the fused flower petals without getting in to obtain and spread pollen.

No thanks to those bees, the flowers of the blueberry plant are open and receptive to pollination for about five to eight days. Each large and healthy blueberry plant has the power to produce thousands of flower buds per year and each flower bud can develop into 16 individual flowers. Each flower is a potential berry. Thus, if all goes well, blueberry plants are capable of 100 per cent flower to fruit set, though 80 per cent is more likely. I’ll take those delicious odds!

Bee-loved blueberries are beginning the season right, flowering and inviting collaborators to dive in. These antics are sure to please those blueberry and pie-lovers come summer. So, even though the blueberry is the star of this article and of the dessert table, it is the humble bee (the bumblebee) that deserves the credit: in St. John Chrysostom’s words, “The bee is more honored than other animals, not because she labors, but because she labors for others.”


Suzan Bellincampi is director of the Felix Neck Wildlife Sanctuary in Edgartown.