Winter Care for Native Bees

If you are doing your part for pollinator diversity by raising mason bees, leafcutter bees, or mixed native bee habitats, then take a few extra steps now to ensure the continued health of these important native species:

Mason bees

1) In October, carefully harvest cocoons from nesting blocks or tubes. Inspect for chalkbrood, parasitic wasps.

2) Wash cocoons in cleaning solution of 1/4 tsp. bleach in 1 cup water.  Gently stir and swirl them around for about 2 minutes.

3) Rinse cocoons in water

4) Spread and allow to air dry thoroughly

5) Store in refrigerator for winter.  Storage container must breath.

6) Release in early spring. Place cocoons on top of or right next to fresh nesting tubes or blocks.

Leafcutter bees

1) Remove nesting blocks or tubes from bee house in October.

2) Store in cool to warm, dry location.  Protect from bugs and rodents.

3) In late April or early May, harvest cocoons carefully.  They will still need 3 to 6 weeks incubation time, but should be emerging as the summer garden begins to flower and temperatures become consistently warm – mid to late June. Do not wash.

4) Incubate cocoons in a breathable bag or box at room temperature (or somewhat warmer).  Time to emergence will vary – usually about 6 weeks at typical household temperatures, a little faster in a warm location and a little slower in a cool room.

5) Check for tiny parasitic wasps between day 6 and day 14.  Remove and dispose of any you find.

6) Check regularly starting in the third week – emergence can start as soon as day 21, but is usually quite a bit later.

7)  As the first bees emerge, move all cocoons out. Release them next to fresh nesting tubes or blocks.  If you are also raising mason bees in the area, pull any full mason bee tubes to store warm and dry, protected from bugs and rodents.

Mixed Native Pollinator Houses

1)  In October, remove nesting materials.  Store in cool and dry place. Protect from bugs and rodents.

2)  Collect and prepare fresh nesting materials for next year.  Store dry.

3)  Put last year’s nesting materials out to release in March.  Place in a box with holes large enough to allow bees to leave as they hatch (water resistant is a good idea), so old nesting material is not re-used as they return to start laying eggs.  Place new nesting materials out in bee house for them to find.

4)  With a diverse pollinator population, bee emergence can happen from March to late July.  Leave bee release box out as long as possible.