How to Attract Mason Bees: A Beneficial Pollinator

The mason bee is a great pollinator and can work blossoms at a lower temperature than honeybees.

| February 5, 2013

This article is part of our Organic Pest Control Series, which includes articles on attracting beneficial insects, controlling specific garden pests, and using organic pesticides.  

The Mason Bee (Osmia species)

In areas where cool temperatures limit honeybee activity during the spring blooming of fruit trees and blueberries, native mason bees are the pollinators that get the job done. Smaller than honeybees with dark bodies that often have a metallic sheen, mason bees can work blossoms at lower temperatures than honeybees. In much of North America, mason bees emerge when the redbuds bloom, with populations highest during apple blossom time.

Sometimes called orchard bees or blue orchard bees, most mason bees are solitary insects that nest in holes in trees, or in hollow stems of old elderberries, brambles or similar vegetation. Mason bees are so named because they pack mud into their nests, like brick masons.

Females are motivated to collect pollen because they include a ball of pollen with each egg they pack away into a mud-lined cell. After six weeks or so of busy pollen and mud collection, adult mason bees die and there is no further activity until the following spring. 

Mason Bees Are Prolific Pollinators  

Adult mason bees sip nectar as they gather pollen from a wide assortment of flowers, but they prefer to find good pollen sources within 300 feet of their nests.

Up to 1,500 blossoms per day must be visited to gather enough pollen to provision the next generation, so mason bees can be phenomenally efficient pollinators of fruits. Only three female mason bees can serve the pollination needs of a mature apple tree. 

12/31/2014 5:08:28 PM

hey, stufflebeam, don't but your mason bees in the fridge! It's a common misconception that it's good for them, but your bees should stay from 50-60 degrees at least - the cold can kill them. Good luck!

2/12/2014 10:24:07 AM

I read somewhere about keeping them in the refrigerator. Any advise on the do & don't of this?

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