Wednesday, April 15, 2015
The gardening season is young, but mason bees are out for their short but productive foray into the blooms of your backyard.
These solitary native bees — most commonly the blue orchard mason bee (Osmia lignaria) — get busy before honeybees and set to work on early-flowering plants like forsythia, pieris and especially fruit trees.
“Mason bees fill a spot in the season when other pollinators are not out,” said Brooke Edmunds, a horticulturist with Oregon State University’s Extension Service. “They’re really important for fruit trees, especially in cool, wet areas.”
As honeybees continue to struggle for survival, mason bees take on a bigger role in the backyard garden, according to Edmunds. Both serious and casual gardeners welcome these earnest pollinators to get better yields of fruits, vegetables and flowers.
Mason bees are smaller than honeybees, have a bluish hue and are often mistaken for flies. Rarely do you have to worry about being stung because these unaggressive bees live alone and have no hive to protect.
Unlike honeybees that fly up to four miles to find their preferred food, mason bees don’t go much farther than 300 feet. They move in a zigzag pattern, which makes them especially efficient pollinators for small spaces, according to Edmunds.
The single-minded bees live to bring nectar and pollen back to the nest for their larvae that hatch from eggs laid between walls made of mud — another material the female bees must haul back to the nest. Leaving patches of mud close to nesting areas in trees or other wood will help attract them, Edmunds said.
You can also encourage mason bees by creating a garden that includes plants that bloom during their excursions in March to mid- or late May.
Consider plants such as crabapples, redbud, flowering currant, elderberry, huckleberry, Oregon grape and lupine.
Even the often-dreaded dandelion is a great source of food.
If you want to introduce the bees rather than wait for them to arrive in the garden, Edmunds recommends purchasing a nesting house, which contains straws filled with cocoons that hatch in spring. They’re available online or at garden centers.
Alternately, you can drill holes into a solid piece of untreated wood. Make the holes five-16ths of an inch in diameter, six inches deep and three-fourths of an inch apart. Insert paper straws with cocoons inside the holes.
Whatever you end up using, hang houses or containers under eaves or other protected areas where they’ll be protected from wind, rain and sun.
Some people will bring the cocoon-filled houses inside over winter to keep them out of reach of predators. They’ll also spend time removing cocoons and washing off mites or parasites and reinserting them into clean straws.
“There are two schools of thought,” Edmunds said. “Some people want to get into high maintenance and harvest, clean and store cocoons. But that’s not necessary. You can always buy additional cocoons each year. And, of course, give the bees the plants they need to keep them around.”