Mason Bee Information*

Mason Bee photo by Brian BrewWhat is a Mason Bee?

  • The Mason Bee, or Osmia Lignaria, is solitary bee that is black, with a blue sheen and is only about 2/3 the size of a honey bee. Like all bees, they have antennas, and their legs are more bee like then a common fly.  
  • Orchard Mason Bees are native North American insects and are found in 46 of the 50 US states.
  • The mason bee doesn’t produce honey, but is a significant help in pollinating fruit and nut trees, and any berry bush blooming between April and June.
  • Like all bees, it lives for just 6-8 weeks between April and early June.  Hive bees have similar life spans, but are replaced throughout the year.

Mason Bee photo by Brian BrewWhy Have Mason Bees?

  • It’s an easy-to-manage alternative pollinator (along with the other 4,000 species of bees, wasps, and hornets)
  • In comparison to honeybees, they fly in lower temperature and are more productive
  • They are probably already in your backyard

Don't Bees Sting?

  • Orchard mason bees are solitary and don't require a hive to protect them. They rarely sting unless held tightly in your hand or potentially are caught in clothing.  Their sting has low venom, and is similar to that of a mosquito bite.
  • They are extremely non-aggressive.

Life Cycle of the Mason Bee

  • The life cycle of a Mason Bee is about 6 weeks. In the Spring, around early to mid April, the males emerge first and begin sunning themselves, waiting for the females. During this phase, the males will forage for food, but are primarily interested in waiting for the females to emerge.
  • After the females emerge, they will initially forage for food for a couple of days.  During that time, they mate with the males.
  • The female finds a hole of about 5/16th inch and places pollen and nectar (12-15 trips) in the back of the hole. She then places an egg onto the pollen/nectar provision and plugs that chamber with a thin mud plug (another 12-15 trips!)
  • The female will continue to lay approximately 20 eggs in about 4-6 weeks. Each egg is enclosed with its own protective chamber within the nest.
  • The mason bee can choose to fertilize an egg or not, thus, they lay female eggs at the back of the hole and the males are placed in the front.
  • A hole of 5/16" diameter and 6" long will typically hold 3 females and 5-6 males.
  • Within 4 days, the egg turns into larva, which begins eating the nectar/pollen in their chamber.
  • Within 1 month, the food supply is gone and the larva spins a cocoon. By the end of September, the final molt has occurred and the cocoon now contains an adult bee.
  • The bee stays dormant until the temperature rises again to about 55° Fahrenheit for about 3 days of the following year.

Various Studies on the Mason Bee

  • When used in a cherry orchard, they can produce a yield of 2-3 times that of honeybees. (Jordi Bosch, William Kemp, Glen Trostle, 2006)
  • When used in an apple orchard, the mason bee produces higher quality apples than honeybees.  (more seeds are pollinated created better shaped fruit)  (P.F. Torchio, 1985)


* Some content courtesy of

What our Partners say:

After 5 years I thought I’d become pretty good at Mason Bee keeping; then I met Dave. He persuaded me to use his bee “housing” and babies. I was skeptical but agreed to a side-by-side comparison with my setup. I was amazed to see the bees far preferred his tube system, and how many more berries, fruits and seeds there were in my native plant restored areas. The birds and other critters are loving it!
I’m working with Dave from now on because his methods are the best and the bees are robust. Best of all, he does most of the work while I get most of the fun.

Jan Hunt
Woodinville Garden Club