Mason Bee
Beneficial insect · Pollinator
Mason bees are gentle, solitary native bees that are highly effective pollinators of spring-blooming trees and garden crops. Unlike social bees, each female builds and provisions her own nest. They are especially active during the cooler part of the growing season.
How to identify it
Adults are small to medium-sized bees, often dark metallic blue, green, or black, with dense body hairs. Females carry pollen on the underside of the abdomen rather than on the hind legs. Immature stages develop in narrow cavities that are partitioned into separate cells with mud or similar natural material.
How it helps your garden
Mason bees are excellent pollinators of apples, cherries, plums, berries, and many early flowers. Because they move among blossoms efficiently, a small number can provide strong pollination in a home garden. They are also important visitors to native spring wildflowers.
How to attract it
Grow early-blooming trees, shrubs, and perennials to provide pollen and nectar when adults emerge. Leave or create natural nesting opportunities such as hollow stems, beetle holes in dead wood, and other small cavities. Keep a patch of moist bare soil nearby, since many species use mud to seal nest cells. A shallow water source and diverse spring flowers help sustain them through their active period.
Tips
Do not assume all bees nest in hives, since mason bees work alone and are often very unobtrusive. Hollow plant stems left standing through winter can support future nesting. Their short seasonal activity means spring habitat matters most.
General guidance for US gardens. Broad insecticide sprays harm beneficial insects along with pests; for a local pest-management plan, contact your Cooperative Extension office. Page updated Aug 4, 2026.