I asked this question 4 or 5 days ago but didn't get a response (I did check...

Asked March 13, 2014, 8:26 PM EDT

I asked this question 4 or 5 days ago but didn't get a response (I did check my junk email folder). We have a small community garden in Arden Hills. We would like to increase pollination in the garden and someone heard that we could try to introduce Mason bees since they are stingless and wonderful pollinators. We know where to get "houses" for them but we heard that we need to be careful to get bees that have been raised in zone 4 so they can survive the climate. We don't know where to get them. I tried the Entomology department at the U but they referred me back to you.

Ramsey County Minnesota

1 Response

Here is a article from one of our Master Gardeners.

Do Your Homework Before Ordering Mason Bees

With honeybee populations declining in recent years, gardeners have been searching for ways to encourage other pollinators to stop by and help out. One pollinator I hear mentioned more and more often is mason bees, and seed catalogs are increasingly offering all kinds of mason bee nesting boxes. They’re cute, these little bee condo things with all those little round holes. So I got to thinking I should buy one. But then I stopped myself, wondering if it was okay to just introduce mason bees to my garden, my neighborhood, Minnesota? I emailed Jeff Hahn, a helpful entomologist with the University of Minnesota Extension Service, and he said he didn’t know a lot about mason bees. But he recommended I talk with Joel Gardner, a grad student who is studying them. Joel didn’t have a lot to say, but what he did tell me made me think I need to do more research before ordering up some bees and a box. (Bees are sold separately.) Native bees, including mason bees, Joel says, are “always a good thing to invite into the garden.” Describing mason bees as “efficient” and “unobtrusive”, he told me that they don’t sting unless you really act like a whack job and grab and squeeze them. Don’t do that, and you can pretty much rest easy while gardening in their presence, even if you get close to their home. What you do need to be concerned about is disease buildup, Joel says. Nests must be periodically cleaned or else fungus spores and mite populations can increase to the point where the nest can be harmful to the bees. If you want to purchase mason bees, you need to be aware of the species you’re ordering since many bees are offered by out-of-state sources. Basically, the mason bee (Osmia lignaria) has two subspecies: Osmia lignaria lignaria and Osmia lignaria propinqua. “Lignaria lives east of the Rockies and propinqua lives west, and introducing them outside their native range should be avoided,” Joel advises. Otherwise, you run the risk of spreading outside pests or diseases to local bee populations. And there could be other problems too. After doing only a little bit more research on mason bees, I found that there is currently a lot of debate about the risks associated with the willy-nilly, nationwide shipment of these popular bees. From what I can tell, it’s just fine to get some. Just be sure to buy the right ones for your zip code. You’ll know you’re dealing with a reputable seller when they offer bees in this way.


  • Crown Bees is a good website to look at for more info. They’re not local to you, so won’t give the best Minnesota-based advice, but they won’t ship you non-native bees, and the website has lots of information and pictures of ways to prevent buildup of pests. I got my mason bees from there, and I can also vouch for their great customer service, which seems more service-oriented than sales-oriented.
    February 24, 2012
    • Meleah
      Hi Michelle,
      Thank you! I just took a look at Crown Bees and they have a lot of helpful information, as well as excerpts from writings about the problem of shipping non-native bees. I think I will get some mason bees this year once I read up on them a bit more. I appreciate your thoughts.
      February 24, 2012
    • Tim
      When do you release your mason bees in MN?
      March 25, 2012
      • Meleah
        Good question. Mason bees are typically orchard pollinators. They need to be released when they’ll have a food source available, so it’s best to wait until some plants are in bloom, which is usually late April or early May in Minnesota. Raising mason bees successfully is not difficult, but there are some important things to understand. I would recommend reading the “What to Do” section of the Crown Bees website: http://www.crownbees.com/category/what-to-do/getting-started.