We’ve hinted about adding honeybees to Curbstone Valley this year, and in fact, we’ve already ordered our bees which are expected to arrive in early April.

In the meantime though, we’re not devoid of bees. In addition to our native resident bumble bees, sweat bees, and feral honeybees, we also have Orchard Mason Bees (Osmia lignaria).

A female Mason Bee peers over the edge of our Mason Bee habitat

More than 400 species of Mason Bees are native to North America.  Unlike honeybees they do not reside in communal hives with a queen.  Mason Bees are solitary bees, and do not produce honey.

We may have already had some Mason Bees here, they can be difficult to spot, as they tend to resemble large flies rather than the traditional honeybees we’re used to seeing.  To be sure we had some Mason Bees here though, last spring we purchased a Mason Bee habitat, and some dormant bees, and installed them under the roof of our workshop, facing south toward the orchard.  Why though, if they don’t produce honey, would we want Mason Bees on the farm?  For pollination of course!

There are a few advantages to having Mason Bees. The first is that beyond specific habitat requirements, Mason Bees need no direct care.  They need food resources, access to damp soil, and a place for brood (the next generation of bees).  That’s it.

Our mason bee habitat contains removable and replaceable paper-lined cardboard tubes

Mason Bees, as they have no hive or honey reserves to protect or defend, don’t sting.  They’re very placid bees to have in the garden, and aren’t bothered in the least by gardeners. They are capable of stinging, but they really have no incentive to do so.

In addition to requiring minimal care, and having placid dispositions, Mason Bees are efficient pollinators.  Toward the end of a normal winter here, as the weather begins to warm, Mason Bees begin to emerge, sometimes well in advance of honeybees in the late winter, usually as the first blossoms on our fruit trees in the orchard begin to bloom.

Our Flavor Delight aprium is just starting to bloom, and the Mason Bees should begin to emerge very soon

The male Mason Bees usually hatch first, for reasons that will become clear in a moment. The males only live for approximately a month after hatching, as their sole purpose is to mate with the emerging females as they hatch.  The females however, with much work to do, live for approximately three months.

Once they hatch, and are mated, the females seek out suitable nesting sites, often the same sites from which they themselves hatched.  They lay eggs in small tunnels in wood (or in artificial habitats like ours).  Eggs destined to be females are laid first, toward the rear of the tunnel.  Each egg is left with food in the form of pollen and nectar, and then each egg is sealed behind a thin ‘wall’ of mud.  Forward of the wall, the next egg is laid, food is deposited, and another wall is built.  The construction of these mud walls within the nests is how these bees acquired the name ‘Mason’ bees.

We purchased two tubes of cocooned bees last winter, and each tube contained 6 bee cocoons

Eggs destined to be males are deposited closer to the tunnel entrance, and these will hatch before the eggs containing the females, which were laid in the back of the tunnels.

Once a tunnel is filled, the female will find another adjacent tunnel, or nearby nesting site, and begin the process again.  Laying eggs, adding food, and building walls, throughout the spring.  During this activity she will make numerous foraging flights for food.

To install the cocooned bees in their habitat, we simply replaced two of the nesting tubes with the tubes containing the bees (arrows)

Honeybees gather pollen and return most of it to the hive where it is stored and used as food for other hive members.  Mason Bees don’t use a hive, so the pollen they gather stays with them, except for the small amounts deposited with their eggs as food for future young.

Mason Bees are rather hirsute, fuzzy little creatures, and not the most hygienic of bees.

This pair of Red Mason Bees (Osmia rufa) are very fuzzy!

It’s not unusual to see a Mason Bee almost completely coated in pollen.

As they travel from flower to flower, the pollen sticks to their hairs and is dragged around with them, and thus their slovenly pollen-coated selves result in a relatively high pollination efficiency.

Each cardboard nesting tube in our bee habitat has a paper liner. The liners and/or tubes can be replaced as they become soiled.

On a per bee basis, Mason Bees are reportedly more than 100 times more efficient than their honeybee or bumble bee cousins. That however is somewhat misleading in regards to overall pollination, as without a hive structure, the number of Mason Bees in a particular location is significantly less than honeybees.

By mid-summer our Mason Bees are usually gone for the season.  During this time, and over the course of the ensuing 9 months, the eggs laid in the nests mature.  Mason Bees pupate in the same cell where the egg was deposited, consuming the food left for them, and the following early spring they emerge from their habitats as mature adult bees, and the cycle begins again.

Our bees are still snug in their tubes. You can see that last summer the female bees laid eggs in at least three of the tubes, whose ends are visibly sealed with mud

Last year we were so busy getting the gardens fenced, trees planted, and raising chicks, that managing honeybee hives seemed rather daunting.  After taking a class at a local nursery though, Mason Bees seemed to fit the bill perfectly, as at the time most of what was blooming in the garden were the fruit trees in the orchard.

If you’re interested in adding Mason Bees to your own garden, or simply want to add a Mason Bee habitat to encourage your native Mason Bees to nest in your garden, a number of online resources carry Mason Bee supplies, and some local garden nurseries sell cocooned bees and supplies in the late winter to early spring.

If you choose to construct your own wooden Mason Bee house, don’t use treated wood!  For the nesting holes, studies have shown that Mason Bees prefer to nest in holes that are 5/16 of an inch in diameter, and between 3-5 inches in length. Holes that are too large will make the cocooned bees vulnerable to predation.

A home-made Mason Bee house, built by Robert Engelhardt (Image source: Wikimedia Commons)

For ease of maintainance, wood block nests can be constructed to use the same cardboard tube liners as the commercially available nest we installed.

Needless to say with spring approaching there’s a lot of buzz around here at the moment.  As our gardens are expanding, along with our planting plans, this spring we are augmenting our native pollinator reserves with two honeybee hives…but we’ll save the details of that for our next post!


If Orchard Mason Bees are not available locally, we’ve seen bees and bee habitats available through the following online sources:

High Country Gardens
Organic Control, Inc. (Orcon)
Peaceful Valley Farm & Garden Supply
Territorial Seed Company