The Orchard Mason Bee (Osmia spp.) is an often-overlooked bee species. While we often think of the honeybee and the bumbling bumblebee when we think about bee species, the mason bee is a quiet little bee that can do tremendous work in our gardens.
Bees have a special relationship with flowers. They visit the flowers to collect food in the form of nectar, and while they are there the bees pick up pollen on their legs. They deposit this on different flowers in the garden as they visit them to drink the nectar, and this allows the flowers to be fertilized and create seeds.
Mason bees are found in Europe and North America. They live in small holes in wood, and often gardeners construct special houses for them to encourage these bees to come and visit. Unlike the honeybee, the mason bee lives a solitary life. It hatches from a hole in the spring and lives for up to a month, gathering pollen and nectar. The female bee nests in a hole and collects mud from the garden to fill the hole with eggs, pollen, and little mud apartments for its babies. Mason bees rarely sting unless they are squeezed or caught in clothing.
You can create a mason bee nesting block. Drill holes in a piece of untreated wood. Use a 5/16” drill bit to create the holes and make them about one centimeter apart. Hang the block in a place that gets the morning sun. You can also use a paper towel tube or a plastic drink container and fill it with drinking straws. Sometimes bees will accept this as a substitute for a wooden nesting block.
To attract the first mason bees to your yard, make sure that there is a source of mud nearby. These bees also love the flowers of Pieris japonica whose leaves are shown at the top of this page. These bushes may attract the first mason bees to your yard. Create a house and soon you will be in love with these industrious bees.