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Increase Pollination With Mason Bees

© Susan Ward

How's have the crop yields been in your garden the past few years? If you're like many gardeners, you've seen a definite decrease in the yield of crops such as apples, pears, peaches, blueberries, and tomatoes. Pollination is becoming a serious problem for home and commercial gardeners alike, as more and more honey bees are destroyed by parasitic mite infestations. Fewer bees equals less pollination, and approximately 80% of crops in B.C. are dependent on pollination by bees.

You can increase pollination in your garden by providing homes for Mason Bees (Osmia lignaria). Mason or Blue Orchard bees emerge in early spring and unlike honey and bumble bees will fly in our cool, wet weather.

About two-thirds the size of honey bees, Mason bees look more like bluebottle flies than bees, but they gravitate towards flowers and are amazingly efficient pollinators. They're called Mason bees because they build nests with walled-off chambers for each of the eggs they lay. Native to our West Coast, they nest in pre-existing holes in trees, such as the ones left by woodpeckers, or even in the spaces between roofing shingles - wherever they can find a suitable hole.

Mason bees are not borers, and will die before laying their eggs if they can't find a suitable home. They like environments with lots of pollen-producing plants, and have a preference for feeding on the flowers of stone fruits, such as apples, which makes them ideal residents of the urban or rural garden.

You can help save the Mason bees and help your garden by providing Mason bee houses. Many commercial enterprises offer a variety of "bee condos" ready to be hung in a sunny, South facing spot in your yard. BeeDiverse Products in Coquitlam, for instance, offers a full range of Mason bee houses, related bee-keeping products, and the bees themselves.

Usually, though, as Mason bees are native to our area, attracting them is just a matter of providing them with a habitat they can live in. You can buy and put up commercial bee houses or easily build one of your own, by drilling 5/16 inch holes 4 to 6 inches deep in a block of wood, or by bundling together cardboard tubes with a 5/16 inch diameter. The holes have to be blocked at the back end for the bees to feel secure. Although Mason bees are also known as solitary bees, they like to nest close to each other, so you'll want to make sure you have plenty of 'holes' in your bee condo for them to move into.