My advice: Don’t shelter your bee hotel for the winter. Let it freeze along with everything else. This post explains why.
Early bee emergence
Last year, for the first time, I hung up a bee hotel. This is a set of nesting tubes designed to make it easier for solitary/native bees, such as mason bees, to reproduce. It seemed to be quite successful, per the picture below. Ultimately I ended up with about 15 nesting tubes filled.
I left that up through the summer and fall, and, per common internet advice, moved it to a sheltered location once winter set in. In this case, I moved it to the inside of a detached, totally unheated garage.
Moving a bee hotel to a sheltered location, for the winter, is probably not a good idea. Despite that being widely suggested by seeming experts. That’s because if your sheltered area is even a little warmer than the outdoors, I think it entices the bees to emerge too early.
That’s what appears to have happened this year. For my particular Home Depot bee hotel, the nesting tubes that were filled by mason bees last spring …
… are all now empty.
Consistent with that, my wife noticed some bees on her crocuses this morning. Which was odd enough to stand out. Because, among other things, not much is blooming right now except crocus and daffodil. And it’s not all that warm out yet. The upshot is that it seems a little early to be seeing bees out and about.
I’m betting that those were “my” bees. And I’m betting that I did them no favors by (inadvertently) waking them up too early, this year. If I put up a bee hotel again this year, I’m just going to leave it alone. I’m now of the opinion that bees ought to overwinter at exactly the temperatures they’ll face out-of-doors.
Like Tinder, but with only 15 people using it.
Experts say that mason bees should emerge when blossoms are open, and daytime temperatures consistently reach 55F (reference).
By those benchmarks — blooms and temperature — my bees are at least three weeks too early. That’s based on these observations.
Blossoms: Slim pickings. At present, only the crocuses, daffodils, and maybe a scattered other few species blooming. There are a few cherry trees here and there, in this area, in blossom. For reference, the earliest recorded peak bloom date for the national cherry trees is March 15, with April 1 being a typical date (reference March 15 to the National Park Service). Separately, a harbinger of spring in many areas is forsythia, but our forsythia isn’t even close to blooming yet.
Temperatures: Still too cold. We’ve had a couple of days where the high exceeded 55F, but those are still few and far between. We are not consistently 55F and higher. But we’re closing in on that.
Source: Weather underground.
And based on our historical weather averages, you wouldn’t expect consistent 55F and higher days for another two-three weeks or so.
Source: Analysis of NOAA weather data for Dulles Airport (Sterling, VA).
All of that, plus my experience last year, tells me that my little batch of bees emerged the better part of a month too early. Call it three weeks, minimum.
Finally, these bees don’t live very long. They emerge, eat, mate, and die within a span of a few weeks. They’re now out of sync with their species in general, and they’re going to be dead before the rest of the local mason bee population emerges. So, if they all survive, their procreation will be as described in the section title.
Conclusion
I’m not a bee expert, but I’ve spent a lot of time observing the habits of bugs, since I took up gardening during the pandemic. The one universal rule is that everything in the garden — plants and bugs alike — operates on temperature, and on degree-days.
By keeping this bee hotel in an unheated garage, I kept it warmer than the ambient outdoor temperatures. I suspect that, one way or the other, this caused my bees to emerge earlier than is optimal, for their species.
If I do this again this year, I’m going to leave the bee hotel outside all winter. The bee larvae may not much like the cold, but they need to stay in sync with outdoor temperatures, in order to emerge at the right time.
Source; All the pictures for this post are from Gencraft.com AI, with the prompt of “a bee, wearing a stocking cap and scarf”.
Addendum: To bee, or not.
Edit: In the end, I gave it another go, doing it better this time, as explained in Post #G24-008. This year, my bee hotels are ugly, but properly constructed (closed-ended tubes roughly 6″ long), as shown above. Well over half the tubes are now filled, as of this writing (4/22/2024). I’m just going to leave them be until its time to take them down and put them in an emergence box next spring.
Original post follows.
Am I going to put up bee hotel this year? Not sure, but at this point, I’d say, no not. Probably not going to put up another bee hotel this year. For the following reasons.
First, these bees don’t pollinate my garden. They’re out and about early in the year, and they are gone by the time my garden crops or flowers need pollination. So when you hear about “attracting bees to your garden to get better yields”, they ain’t talking about mason bees. The earliest-blossoming food I grow is peas, and my recollection is that mason bees do their thing well before (e.g.) the peas blossom. Apparently they are good for orchards. Which would make sense, as fruit trees blossom early. (And mason bees are orchard bees, or orchard bees are mason bees, or something, I’m not entirely sure. I don’t have an orchard.)
Second, I’m trying to grow the kinds of plants that (the internet tells me) make good natural nesting sites for these bees. But that whole enterprise is looking a bit sketchy at the moment. I’ve started down that path, by not mowing my wildflower beds yet.
You’d think, well, that’s got to be dead easy, just grow some plants and leave them. Just don’t mow.
But its not that simple.
Mason bees need medium-sized hollow stalks to nest in. (Or equivalent.) That seems right by my experience so far. Sturdy annuals will sometimes leave behind big, ugly stems. Looks about the right size.
But that’s the point where anything ceases to be easy.
In a nutshell, you have to keep them for two years, they’re ugly, they get in the way, and you have to defend them from the deer. I’m not going to go through the details. I can boil it down to this.
Do I really want to use my time and attention to try to protect some ugly weed stalks from ravenous end-of-winter marauding deer? For a couple of years, yet (the literal same batch of stalks, I mean.) And somehow work around them, while prepping the beds for this year’s flowers. And in the end, really have no clue whether they are effective or not.
I have a lot of sunk cost in this whole bee-hotel thing, not in the sense of buying the Home Depot wooden bee hotel, but mostly in the time and effort gathering and cutting bamboo, in anticipation of annul replacement of the nesting tubes in that hotel.
In addition, rehabbing that Home Depot hotel for re-use could be a fair bit of work. I should replace the bamboo nesting tubes each year. This year — with the off-the-shelf unit — that means breaking the existing glued-in tubes out first.
I think I’ll see how hard the rehab is, first, then decide on next steps after that.
But as of right now, I’m not seeing a huge benefit to anybody or anything in being a mason bee hotel keeper for another year. I should let them find their equilibrium vis-a-vis the local flora. Might tweak the flora to try to help them out, if I can figure out how to do it. But I think I’m going to punt on maintaining a manufactured bee hotel.
