Blue Orchard Mason Bee Calendar
For the Willamette Valley- check with your extension office for dates in your area.
January - June
Provide water, mud and early flowering plants. Mason Bees prefer natives.
Put out Mason Bee blocks or tubes in your houses (not the cocoons yet). Depending on the weather, Mason bees nesting houses, blocks and tubes can be put out in mid or late February, but by early March at the latest. A local population of Mason bees that did not emerge from your nesting system may be looking for “holes” to place their eggs.
Late March - mid April
Put 1/2 to 1/3 out your cocoons in late March and the rest 1-2 weeks later. (25 Minimum in each batch) The weather will determine when you put out the cocoons. Look for temps of 50-55° for 3 or more days in a row with no heavy rain forecast. All cocoons should be out no later than mid April Do not fill the emergence tube more than half full. If your cocoons are in your refrigerator, where they should be they will be OK there while waiting for good bee weather. Other factors to consider: are lots of flowers available now?
Take Tubes or Blocks and place them inside a paper bag- fold over- staple. This is to protect the cocoons from a parasitoid wasp that feeds on the bees as well as to protect them from mice, earwigs, and ants. Place in a warm, but not hot location, so the bees are warm enough to complete their development. (ie, garage-but not hot top shelf or a closet)
Harvest cocoons from blocks or tubes.
October – March
Store cocoons in your refrigerator. (In frost free refrigerators, near the cocoons add a small cup of water with a damp paper towel that acts as a wick to maintain humidity in the container.)
Cocoon Harvest Workshops
Registration opens in September. Preregistration is required due to space limitations. Register and see workshop locations/times at the Linn County Master Gardeners website, or call 541-967-3871.
Mason Bee House Placement:
Mason bees are so-called, because they use mud in the construction of their nests, however, it is actually the common substitute name used to describe bees belonging to the genus ‘Osmia’ which are part of the family ‘megachilidae’. They are sometimes called Blue Orchard Bees.
For more information check out the following Mason Bee publication: https://catalog.extension.oregonstate.edu/em9130
Stay tuned for more information on Bee Notes and at the next BEEvent Pollinator Conference.
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Bee Notes are periodic emails and reminders from Linn County OSU Extension
about bees and other pollinators. We do not share your information.
These posts are from Master Gardeners, as well as speakers we have had at various events concerning pollinators.