Up Close: Mason Bees

By Lisa C. Originally published Feb. 10, 2016



Despite their name, mason bees aren’t part of the Illuminati and don’t want to rule the world—they just want to pollinate it.

“Honeybees are terrific pollen gatherers, but mason bees are phenomenal pollinators,” said Dave Hunter, founder of Crown Bees in Woodinville. “Honeybees make honey, but mason bees make food.”

A national expert on mason bees, Hunter has devoted his life to educating the masses about these non-aggressive, solitary bees. Read on to discover what makes mason bees different, and how to become a good steward to this personable pollinator.



Humans have relied upon native bees, such as mason bees, to pollinate crops for millennia. Native bees are wild—they are solitary, don’t live in hives and don’t make honey—but they live to pollinate.

With the emergence of monoculture—growing a single crop—and increasing crop size, farmers began using honeybees as the chief pollinator. Why? Hive-dwelling honeybees can be easily managed by humans.

Bees 1

Honeybees are social and dependent on each other, living in colonies of 50,000 or more. This makes them transportable—just pick up the hive, put it on a truck and move it to a new location. And because honeybees make honey, hives are also a commodity.

Today’s reliance on honeybees as a chief pollinator has increased their population density, resulting in diseases, viruses and pests spreading quickly from colony to colony. This can result in massive bee die-offs.
Having healthy pollinators is essential to human existence, as a third of our food is pollinated by bees.

Cue the mason bee.

Interest in the gentle-natured, rarely stinging mason bee is burgeoning as farmers and homeowners turn to these pollination powerhouses for naturally bountiful bumper crops.
Just one mason bee pollinates as well as 75 honeybees—and that’s a conservative estimate.

Native to the Pacific Northwest, the Blue Orchard Bee (Osmia lignaria) is a striking metallic-blue color. About the size of a fly, and often mistaken for one, this mason bee’s unassuming appearance belies its pollination prowess.

Bees 2


To appreciate why mason bees are so amazing, consider the following non-comprehensive bee primer.

Social bees, such as honeybees, make up just 10 percent of the 20,000 known bee species in the world. Each hive has one egg-laying queen. Supporting the queen are up to 50,000 worker bees that collect nectar or pollen, and nurse bees that tend to larval bee babies.

Worker bees forage for either pollen or nectar during a single trip (but not both). They visit one type of flower, pollinating a single species, until that source is exhausted.

When foraging for nectar, honeybees slurp nectar into their honey stomachs, which is later regurgitated and transformed into honey, their wintertime food. When procuring pollen, a protein-rich food source, they collect it in pollen baskets—the orangey wads on their back legs—to be shared with the hive.

“Those big pollen pockets on their legs aren’t for pollination—it’s bee food for thousands of bees,” Hunter said.


To illustrate the power of mason bees, Hunter told a recent story about a farmer in Omak, Wash. The farmer had nine acres of cherry trees, and brought in mason bees to pollinate his crop, Hunter said.

“He ended up with six tons of extra cherries per acre last harvest,” Hunter said. “That’s crazy—and that’s possible.”
Mason bees are terrific pollinators because they’re terrible at gathering pollen. Hairy as a Sasquatch, these sweet-natured bees aren’t choosy when it comes to what flowers they like, and they’ll collect pollen AND nectar in the same visit.

“It’ll belly flop onto a flower, grind around and do the same thing on another flower—all in a big circuit,” Hunter said. “She drags her hairy abdomen, mashing pollen into it, dropping pollen everywhere she goes. And she’s cross-pollinating like you wouldn’t believe!”

Bee 3

Solitary bees make up 90 percent of the world’s bees, including our native mason bee, the Blue Orchard Bee. In solitary bees, each female is a queen—a queen!—and isn’t supported by a hive. Instead of hives, a mason bee creates its brood chambers in an existing hole, such as reeds or mason bee tubes, for the 15 to 20 eggs she will lay.

A mason bee’s sweet disposition is a product of its short life—six weeks for the ladies, and just two weeks for the fellas. Those weeks are devoted to creating the next generation, so they don’t have time to be either aggressive or territorial.

After an early-spring mating with a short-lived Mr. Mason, a fertilized queen forages a 300-foot radius from her nesting tubes for pollen, which becomes food for her future progeny.

She’ll mix pollen with her saliva, roll it into a golden ball inside a tube and lay a single egg upon it. Then, she’ll seal the egg cell with clay (hence their name, mason bees). She’ll fill each tube with about six egg cells, laying about 15 eggs by her life’s end.

During the heat of the summer her eggs develop into hungry larvae, which fatten up on their pollen reserve. Then, in its pupal stage, it spins a cocoon around itself and develops from pupa to adult bee, before taking a long winter’s nap. During this time, it burns through its fat reserves until it emerges from the cocoon in the spring. That’s it.

Fun fact: The queen lays future queens first, at the back of the tube (farthest from the front), followed by the males. In nature, this ensures the female of the species is most protected—and most likely to become fertilized by the fellas—as they emerge first, waiting for a queen to reveal her queenly self.


Creating a mason bee haven at your home is a simple, inexpensive activity. You can purchase a kit, or create your own.

These bees are easy to care for, especially if you’re afraid of bees. No fancy beekeeping clothes required, because mason bees rarely sting—only if their little bee lives are in danger. Their sting feels like a mosquito bite, Hunter said, adding that there are no known cases of anaphylactic shock resulting from a mason bee sting.

Here’s what you need to get started, in a nutshell: Mason bee cocoons, shelter and nesting tubes, clay-ey mud and blooming pollen sources.


Hunter recommends first-time mason beekeepers to start with 20 mason bee cocoons. A box of 10 mason bees cocoons costs $17.99 and contains four larger queen cocoons and six smaller male cocoons; a box of 20 cocoons is $32.99. They’re in stock now in our garden department refrigerators. Remember, keep cocoons refrigerated until conditions are optimal.


Queen bees love early morning sun—it’s warm enough to get them moving early, and won’t cook them in the heat of the day. Build your own shelter using an untreated cedar board for less than $3.49, or purchase a kit for $14 to $50.


Keep your bees dry and protected by installing the shelter in a south-southeast facing location, about five to six feet off the ground. Once mounted, place nesting holes inside the shelter with hole openings facing out, putting a few twigs between as mason bee “road signs” to help them locate their nest.

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Nesting holes or tubes are essential for mason bees. Choose natural reeds, wooden trays or EasyTear mason bee tubes, ranging from $11 to $50. Or, for free, you can make your own tubes by rolling a quarter sheet of plain paper around a pencil and taping one end. In the fall, each of these materials opens freely allowing for cocoon harvesting.

Hunter stresses that folks should not use drilled wood blocks, bamboo or plastic tubes. Drilled blocks or bamboo don’t allow for cocoon harvesting; plastic tubes trap moisture, and too much moisture encourages mold that kills bees.


This is the No. 1 reason for mason bee failure: no mud, no new bees. Mason bees gather wads of sticky, clay mud in their mandibles to create partitions within their nesting tubes. If you don’t have clay-ey soil (or if you’re not sure), spend five bucks on a bag of mason bee clay. Dig a hole near your mason bee’s shelter, and be sure to keep the clay wet.


Your bee haven is complete if you have at least one native blooming plant in your yard, as well as fruit trees or vegetables.
“Don’t put out your bees if you don’t have pollen,” Hunter said, so make sure those blooms are bangin’.

Stumped on what to plant? Grab a packet of annual seeds, such as Ed Hume’s Pollinator Mix, or consider planting the following bee-friendly crops:

  • Dandelions (yes, dandelions!)
  • Catnip
  • Goldenrod
  • Lavender
  • Penstemon
  • Phacelia
  • Rose
  • Salvia
  • Almond
  • Apple
  • Cherry
  • Thyme

Keeping your yard ecologically balanced means allowing beneficial insects to thrive—even wasps and aphids can be beneficial, Hunter said.

“You need prey for your predators to feast on,” Hunter said. “If your yard has no aphids, it has no ladybugs. If it has no grubs, you’ll have no birds. And if you only have prey, then something has killed off your predators.”

Hunter advises homeowners to eschew pesticides and insecticides, as they throw off nature’s delicate balance. But, if you must use a chemical spray, steer clear of broad-spectrum varieties, and spray in the evening.

“That way, you’ll kill the bug with the least impact to pollinators,” he said.


After purchasing, store cocoons in the refrigerator until daytime temperatures hover between 50° and 55° degrees Fahrenheit in the spring. When temperatures are right and your yard is bursting with a variety of pollen sources, it’s time to free the bees.

Hunter recommends placing cocoons out in thirds.

“If you put all bees out at once and it rains for a week, you’ll lose them,” he said, because the Northwest is prone to catawampus weather.

So, if you start with 20 cocoons, place out two females and four males. Wait a few weeks before placing the next third. Place the mason cocoons inside their bee house, on top of or behind their nesting tubes, so when they emerge they’ll know where they came from.

Hunter Recommends placing cocoons out in thirds

bees 6


Your garden was perfectly pollinated, and you’ve made zucchini bread for every human within a five-mile radius. Your bee tubes are brimming with future mason bee progeny. Now you need to harvest them to keep them safe through winter.

In September or October, bring your nesting material inside and carefully crack ’em open to reveal cocoons. Separate cocoons from leftover pollen, larval poop and mud.

Then give your cocoons a bath. Crown Bees says to place cocoons in a colander and vigorously blast them with cold water while swirling the cocoons around. This dislodges any remaining yuckies.

“Don't be nervous,” says the Crown Bees website. “The cocoons are waterproof and you're not harming the bees any.”

Give cocoons a final rinse and lay them on a kitchen towel to dry a bit before storing them for the winter in your refrigerator. Using a HumidiBee storage container helps to retain moisture—without the proper amount, they’ll shrivel, dehydrate and die.

In spring, the process begins again. Congratulations, you’re now a bonafide mason beekeeper!

“These are wild bees doing their own thing,” Hunter said. “We’re disrupting nature, just a hair, to take care of them.”

Want to learn more? Here are three terrific resources:
Click here to download “An Intuitive Guide to the Gentle Bee” from Crown Bees; watch this episode of national public television’s Growing A Greener World featuring Dave Hunter; and definitely visit www.crownbees.com

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