What is a mason bee?

Mason bees are solitary bees that fly during the spring time. We work with the blue orchard mason bee, Osmia lignaria which is native to the Pacific Northwest. They fly during April and May and pollinate plants that bloom in the spring such as fruit trees, some berry bushes, and many of our native plants. Instead of living in a hive, they use small cavities such as woodpecker holes and rockeries to lay their eggs in.