Mason Bee Calendar Female male
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.
Mid to late Feb 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 to Put 1/2 to 1/3 out your cocoons in late March and the rest 1-2 weeks later. Mid April (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. Another factor to consider- Are lots of flowers available now & for the next couple months?
June 1st Take Tubes or Blocks and place them inside a cardboard box. 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)
October Harvest cocoons from blocks or tubes.
Cocoon Harvest Workshops
Registration opens in Sept. Preregistration is required due to space limitations.
Register and see workshop locations/times at:
www.extension.oregonstate.edu/linn/beevent or www.linnmastergardeners.com
or call 541-967-3871.
October – March Store cocoons in your refrigerator. (In frost free refrigerators, add a small cup of water with a damp paper towel that acts as a wick near the cocoons to maintain humidity in the container).
For more information check out the following Mason Bee publication: https://catalog.extension.oregonstate.edu/em9130
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Mason Bee House Placement:
Optimum height of bee house from ground is about 3-6 feet. Yes it can be higher.
It should be high enough to be above the splash zone, but don’t install it too high- you will want to watch the bees in action!
The bee house should be placed on a wall that receives morning sun, such as the South-East wall of your home. If you don’t have great morning sun, give them as much as you can, bees survive in the wild without this. Your bees just do better with it!
You also need to think where the afternoon sun is as you do not want the nesting box to be in direct sun in the afternoon, it will get too hot for the bees and may kill them.
The opening of the bee house should face away from prevailing winds and rain as much as possible: in order to keep the holes and liners dry.
Don’t place your house too far under a porch, as bees may not be able to find the house easily.
Don’t place the bee house over a pond or water source. Your bees haven’t taken swimming lessons, and many could drown.
Place the bee house away from your bird feeder, bees make tasty morsels.
Have a water/mud supply nearby or put some clay soil with water in the area. Mason bees need mud to enclose their cocoons.
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.
These posts are from Master Gardeners, as well as speakers we have had at various events concerning pollinators. Subscribe to BeeNotes to get this information delivered right to your inbox!