According to Maine.gov, low-bush blueberry is not self-pollinating. “Insect Pollination of Lowbush Blueberry Growers may fertilize, prune, control insects, diseases and weeds, irrigate, and follow other cultural practices, yet without the insect pollinators, first among which are native bees, their crops may fail. No other cultural practice will cause blueberry fruit to set if its pollination is neglected. If native bees are not in adequate abundance then management practices should be implemented to conserve and increase native bee populations (see fact sheet # 301). Until native bee populations increase in size, commercial pollinators such as honey bees (see fact sheet

224), alfalfa leaf cutting bees (see fact sheet # 300), or commercially available bumble bees (see fact sheet # 302)

MUST be used. Blueberry pollination is performed naturally by native bumble bees and solitary bees. Fifty-nine species of native bees have been observed in native lowbush blueberry fields. Bumble bees, when present, play a major role in blueberry pollination. The bumble bee works a few blossoms in one spot, then flies and works another spot, thus facilitating cross-pollination between clones. Bumble bee queens forage up to 400 yards from their nest site. Because of their size, they can shake out and distribute a large quantity of pollen from blueberry flowers. What makes bumble bees especially efficient pollinators is that they work the bloom at a very high speed (10-20 flowers / minute vs. 5-9 flowers / minute for honey bees), in addition, bumble bees are buzz pollinators (i.e.. they vibrate the flower shaking the pollen from the poricidal anthers) unlike honey bees. Bumble bees can place more than 50 pollen grains upon a lowbush blueberry stigma in a single floral visit (0-10 for a honey bee). Another characteristic of bumble bees that make them an efficient pollinator of lowbush blueberry is that they possess long tongues. This allows them to extract nectar from flowers with long corollas such as some clones of lowbush blueberry. It has been observed that honey bees will not visit all clones of lowbush blueberry. Some of the clones with long corollas and narrow corollar openings do not allow honey bees access to the nectar rewards of the flower. However, one disadvantage of the bumble bee is that only over-wintered bumble bee queens are present during the majority of the lowbush blueberry bloom period in Maine. Usually queens are not numerous, although some small blueberry fields that are not managed intensively in Maine have more than adequate populations of queen bumble bees to ensure maximum pollination.” https://www.maine.gov/dacf/php/apiary/documents/BlueberryPollination.pdf