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The ABC's of Mason Bees

All flourishing gardens have one thing in common- pollination. Read on to learn what all the buzz is about.

What are Mason Bees?

Known for being excellent pollinators, Blue Orchard Mason Bees (or Osmia lignaria) look very similar to the common house fly. Their black bodies and dark blue iridescent sheen make them a standout in the garden from the typical yellow and black striped bees many are used to seeing.

The Blue Orchard Mason Bee (Osmia lignaria)

Unlike the Honeybee and other common garden bees, Mason Bees are non-social and do not create a hive. Instead, they use nest boxes (you'll read more about those later) or small holes found naturally in wood and structures. As a solitary bee, they also do not have a queen. This makes them a very docile worker as they have no one to protect. While they work alone, they do like to nest in groups when possible.

Aren't all bees the same when it comes to pollination?

There are over 150 types of Mason Bees. At Airport Garden Center we sell cocoons for the Blue Orchard Mason Bee, a native pollinator to Washington State. As a native bee they do exceptionally well pollinating our native plants, but also do so well pollinating fruit trees and food crops they were named after it (Blue Orchard Mason Bee).

Mason Bees are also one of the hardest working bees and don't shy away from flying in rain. Unlike Honeybees and the Bumble Bee, Mason Bees carry pollen on their abdomen instead of their legs.

Mason Bees have a 95% pollination rate compared to Honeybees (who come in at a measly 5%).

Mason Bees don't travel as far as some other bees, staying within about 300 feet of their nest boxes. For gardeners with larger yards this may mean having multiple nest boxes. For gardeners with smaller yards this may mean you don't have to share your bees with the neighbors!

Different species of bees also pollinate at different times of the season. Mason Bees are an early season pollinator, emerging once temperatures reach about 55 degrees.

Do they sting?

The non-aggressive temperament of the Mason Bee coupled with not having a queen to protect makes them one of the friendliest bees around- males don't even have a stinger! It is still possible for a female to sting if she feels she is in danger, though many have said their sting feels more like a mosquito bite.

How many bees do I need?

We recommend 10 bees for every fruit tree in your yard. 250 - 500 Mason Bees can pollinate one acre. Each female Mason Bee can lay up to 30 eggs, making each seasons colony larger than the previous.

The Nest

Mason Bee nest box with paper tubes. Mason Bees will use clay and mud to seal off the holes of their nest boxes once their eggs have been laid.

Image by Paul Wheaton

Paper nesting tubes.

Mason Bees are fans of small, dry spaces that allow them to nest with their fellow bees. In the wild Mason Bees will find small holes in pieces of wood or structures. When utilizing the bees for pollination, providing a home (or nest box) is recommended. Nest boxes are small structures built to house several small tubes. The bees use these tubes to lay eggs that will turn into next seasons bees. In the past, Mason Bee "growers" used homes built only of wood, with holes drilled into the wood that the bees used for their eggs. In recent years it has become apparent this system was not ideal as predatory mites and other larvae killing organisms can attach themselves to the walls of the wooden holes and stay there, season after season. For this reason, the use of paper or natural tubes placed into the holes has become the new way to provide your bees with the safe environment they need to thrive.

Nest boxes should be secured onto a structure. Avoid mounting them on fenceposts or trees as they often will shift and do not provide the amount of wind protection the homes require. A location that receives early morning sun within several feet of access to mud or clay is ideal. Mason Bees will use the mud or clay to create pockets inside the tubes between eggs, as well as close off the ends of the tubes once full for protection. Keep in mind your bees will travel up to 300 feet from their home, so place it within reach of the plants you wish to be pollinated.

Life Cycle


Last years eggs have matured into hibernating bees.

Set out nest boxes and cocoons.


Adult bees emerge in the early Spring.

Male and female bees mate.

Females collect pollen and nectar.

Females create food stores and lay eggs.


Adult bees die.

Eggs develop into larvae.

Larvae feed on pollen & nectar.

Larvae develop into pupae.

Pupae develop into adults, protected inside cocoons.


Bees hibernate inside cocoons.

Retrieve nest boxes.

Clean homes and store cocoons in a cool, dry location (33 - 38 degrees F.)

Supply List

Are you ready to welcome the Blue Orchard Mason Bee to your garden?

Here's what you need. Find it all in our Beneficial Insect section.

  • Mason Bee Cocoons

  • Nest Box

  • Paper or Natural Tubes

  • Access to Mud or Clay

  • Early Spring Blooms for the Bees to Pollinate and use for Food


Paper Tube Cutter for harvesting cocoons at the end of the season.

'The Orchard Mason Bee' a book by Brian L. Griffin. (STAFF FAVORITE!)

Wire Brush to clean the wooden part of nest boxes at the end of the season.

Viewing Box for watching your Mason Bees lay their eggs and transition into larvae.

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