While our native bees can be difficult to identify to species, we know for sure this bee is in the genus Osmia and likely in the subgenus Melanosmia, a group known as the metallic green or blue osmia. There are about 150 species of mason bees in North America. They tend to be metallic green, blue-black, or blue-green in color and have beefy little bodies. Most species are active in early to late spring. Depending on the species, they either excavate a nest in the soil or use hollow stems (or bee hotels put out by bee lovers). They lay eggs in individual cells that are made of clay / mud or other materials.
Photo by Lindsay Guttermuth in Missoula, MT