Setting Up a Mason Bee House: Spring and Summer
I hung a Mason Beehive on the side of my house over the weekend, right next to my tomato bed and a pot of petunias. Filmed the whole thing. Thirty seconds, start to finish, no special tools beyond a drill I already owned.
While mason bees are the headline tenant of these hives, the tubes inside don't check ID. Any solitary bee that nests in small tunnels rather than building comb can move in, and over a season, more than one species usually does.
That's good news for me, because despite my best intentions to get this up back in early spring for mason bees, here we are well into summer. Mason bee season has already passed. But for the next wave of tenants, leafcutters and other solitary bees, the timing couldn't be better.
Getting your yard ready for solitary bees of all kinds
Exactly when each species shows up shifts with your climate and the weather in any given year, so there's no single date that applies everywhere. What doesn't change is the basic logic: get the yard ready, a wall to mount the house on, a mud source nearby, and let whichever solitary bee is currently house hunting find it. Here's a quick rundown of who that's likely to be, depending on the season.
Mason bees and the springtime window
Mason bees (Osmia species, the blue orchard bee is the common backyard one) spend almost their entire lives as dormant adults, sealed in a cocoon inside a capped tube, waiting out fall and winter. They break that dormancy in spring once daytime temperatures hold steady around 50 to 55°F for several days running, as early as February in mild regions, into April further north and east.
Males emerge first, several days to a week ahead of the females, and wait near the entrance. Once mated, females get straight to work: provisioning a pollen and nectar mass at the back of a tube, laying an egg, sealing the cell with mud, and repeating until the tube is full and capped.
A female's whole active season runs about four to six weeks, often wrapped up by late May or June. The eggs she leaves behind hatch into larvae, eat their provisions, spin cocoons, and develop into adult bees by late summer, then sit dormant until the cycle starts again the following spring. Almost the entire life cycle happens out of sight, inside the tube.
Leafcutters and other summer tenants
Once mason bees finish for the season, leafcutter bees (Megachile species) are the most common second wave. They need warmer conditions to get going, generally consistent daytime temps in the 70s, so they don't show up until early to mid summer, typically late June through August, sometimes into September in milder climates. A hive installed midsummer isn't behind. For these bees, it's right on time.
That's also where the real upside shows up. Mason bees do most of their work on spring bloomers, especially fruit trees. Leafcutters and the rest of the summer crowd are out pollinating whatever's blooming once the garden is in full swing: squash, melons, cucumbers, and the flowers in between. More solitary bees working more of the season means better pollination coverage, and better coverage tends to show up in the harvest, not just in the flower beds.
You can tell leafcutters from mason bees by the caps on the tubes. Mason bees seal everything with mud. Leafcutters chew small circles out of leaves (rose bushes are a favorite target, so a few notched leaves in the garden is a good sign, not a problem) and use those instead, so the caps have a green tinge and a slightly ragged, papery look.
Small carpenter bees (Ceratina) can show up too, often later in summer, and in mild climates may produce a second generation within the same season. None of these bees are aggressive. They're solitary, they don't defend a hive the way honey bees do, and most people never notice them at all beyond the capped tubes.
Find a south or southeast wall
Before I ever picked up the drill, I found a spot on a south facing wall, four to six feet off the ground. All of these bees are cold blooded, so the heat off a south or southeast wall gets them up and flying on mornings that would otherwise keep them inside, especially mason bees in the cooler weeks of early spring.
Four to six feet up keeps the entrance above most ground-level disturbance (curious pets, lawnmowers, kids with sticks) while staying low enough that I can actually watch what's happening.
Each hive comes with a French cleat and screws. I drilled pilot holes, set the screws, and the house was up. A Mason Beehive is light, the hardware is simple, and there's no leveling fuss the way there is with a full honey bee hive setup. If you can hang a picture frame, you can hang this.
They need mud as much as they need flowers
This is the step most setup guides skip, and it's why a lot of these houses sit empty even in good locations, even with summer tenants waiting in the wings. Mason bees don't just lay eggs in those tubes. They seal each one with mud, then cap the whole tunnel with more mud when it's full. It's the entire reason they're called Mason bees in the first place.
If your yard is dry mulch, gravel, or hardscape with no exposed clay-heavy soil nearby, mason bees can have a perfect house and nowhere to do the actual masonry. I keep it simple: a small dish of soil near the house, kept damp. Wet down some dirt within a short flight of the entrance and let gravity and sun handle the rest. Leafcutters don't need the mud, they bring their own building material, but mason bees won't nest without it.
The checklist
- South or southeast wall, four to six feet up.
- Mount it securely. A drill and the included hardware is all this takes.
- Provide a source of clay-heavy soil within easy flight distance.
- Leave the house up through summer and into fall. If you miss mason bee season, don't worry, leafcutters and other solitary bees are just getting started.
- We highly recommend reading Mason Bee Revolution. It has info about many different kinds of solitary bees.
Our Mason Beehive is built from western red cedar with replaceable paper tube inserts, so you can pull a season's cocoons each fall and start the next year clean. Set it up in early spring for mason bees, or midsummer, like I did, for the leafcutters and other solitary bees just getting started. Either way, more pollinators working through the season usually means a fuller harvest, not just a few extra flowers.
