Presenting: Awbury’s 2018 series on pollinators– from wasps to wind! 

Monthly articles will correspond with our programming and our “Pollinators FOUND at Awbury Arboretum” art show and scavenger hunt.

Articles written by La Salle student and Awbury intern Dan Sardaro.


When it comes to bees, we usually tend to think of a select few that we come across in our gardens or local parks – bumble bees and honey bees are a few that come to mind. However, there are numerous bee species that fill our world and pollinate so many plants around us. The pollinator of the month for March is a bee that often gets overlooked, the Blue Orchard Mason Bee, scientifically called Osmia lignaria. Karen Singer’s tile work this month illustrates a brightly colored Blue Orchard Mason Bee against the pastel bloom of an Eastern Redbud.

Blue Orchard Mason Bee, credit: USDA Forest Service

Blue Orchard Mason Bee, credit: USDA Forest Service

The Blue Orchard Mason Bee is a part of the mason bee group, which are extremely effective at pollinating fruit trees. They are often called orchard bees because of this specialization and are attracted mostly to fruit trees from the family Rosaceae, including apple, cherry, and peach. Without the bee’s help, fruit industries would be at a major setback, and many commercial growers will actually manage live bee populations to keep their produce healthy.

There are many characteristics that differentiate mason bees from other types of bees. For one, a mason bee is a solitary insect that lives by itself. It doesn’t rely on the hive structure that other bees like the honey bee require for survival. Orchard bees (particularly the females) nest in previously made cavities, such as a hollow plant stem or a hole left behind by a woodboring beetle, and without any help, construct a linear type nest with individual, separated cells to house pollen, nectar, and eggs. These bees are quite the recyclers, often reusing a nest made by another bee nearby. Mason bees also have a very distinct appearance. They are a dark blue color with a metallic shine, lacking the striped coloring of their more popular cousins, although they are of a similar size. They also pollinate in a slightly different method than other types of bees. Blue Orchard Mason bees carry pollen on the bottom of their abdomens rather than on their legs.

Blue Orchard Mason Bee tile - of the FOUND exhibit by Karen Singer Tileworks

Blue Orchard Mason Bee tile – of the FOUND exhibit by Karen Singer Tileworks

Blue Orchard Mason Bees are not only a significant aid to agriculture, but they also serve as a great tenant in your own garden, too! Creating home for these little critters is easy – simply drill holes into a block of wood about 5/16 in (7.5 mm) in diameter and 6 in (15 cm) long. They should be spaced about 0.75 in (2 cm) apart. To protect against parasites, inserting paper straws into the holes can help you accessibly screen for parasites and clear out possible dead bees. If interested in starting your own mason bee home, make sure to learn how to check for parasites. Even with the best intentions, a bee home with parasites can have far reaching consequences for other populations in your area. Check out these resources for more information!

Bosch, J., and W. Kemp. 2001. How to Manage the Blue Orchard Bee. Sustainable Agriculture Network, Beltsville, MD.

Dogterom, M. 2002. Pollination with Mason Bees: A Gardener’s Guide to Managing Mason Bees for Fruit Production. Beediverse Publishing, Coquitlam, BC, Canada.

Logan Bee Biology and Systematics Laboratory.

Sources Used:

Moisset, Beatriz, and Vicki Wojcik. “Blue Orchard Mason Bee (Osmia Lignaria).” Blue Orchard Mason Bee, US Department of Agriculture,

Stanley, Cory. Blue Orchard Bee (Osmia Lignaria). Utah State University, Apr. 2012,