Bernheim Pollinators: The Blue Orchard Mason Bee

By Wren Smith

photo by Justina Block

If you stand still for a moment in a garden or any place graced by a variety of flowering plants, you will likely be surrounded by the great hum of life. Stop and enjoy. If you are patient and observant, you may encounter not only our domestic honey bees, but also many native pollinators, including the fly-like blue mason bee. The blue orchard bee, as it is also called, has become established as an alternative orchard pollinator in North America. According to the USDA just 250- 300 females will pollinate an entire acre of apple or cherry trees. A single mason bee may visit 20,000 or more blossoms per day and pollinate 12 lbs of cherries.

Blue mason bees, Osmia lignaria, are solitary and are non-aggressive. Although they can live side by side, they do not form true colonies.  After laying and provisioning an egg with a ball of pollen, the female fashions a clay partition before laying another egg and once again providing it with pollen. These are spring bees and emerge from their cocoons (which remind me of puffed wheat) when the weather reaches 57 degrees.

Mason bee habitat is easy to make. You can provide nesting material for the females in the form of reeds, paper tubes, wood trays with small holes, near abundant flowering plants, and a source of water. Be sure to leave some bare soil for the females to make clay  near the perspective nesting site or bee house.

Justina Block is a passionate advocate for native bees and descendent of our founder, Isaac W. Bernheim, who has established bee houses in several gardens, arboretums, and public locations in the Cincinnati area. Thanks to the generosity of the Justina and the Osmia Bee Company, Bernheim now has three bee houses designed for the blue orchard bee that are currently being used  by these industrious little pollinators. One can be found near the wooden arbor on the path to the Quiet Garden, one near the front of the Education Center, and one in the Edible Garden near the smaller water garden. A fourth one is a part of our native bee display in one of our mobile labs.  Be sure to check these out on your next visit to Bernheim, and look for programs, and upcoming opportunities such as Bugfest to learn more.

Our Newsletter

Sign up for the Bernheim Buzz

Get the "buzz" of Bernheim activity weekly in your inbox by signing up below.

This field is for validation purposes and should be left unchanged.