How You Can Help Native Cavity-Nesting Bees by Managing Your Native Plants for their Needs

We often get questions about using manufactured bee houses to support native bees, so we wanted to provide some basic information and cautions in case you decide to do that. But to be clear, the safest way to help cavity-nesting bees is by leaving cut stems in your garden so the bees can use them. Here’s a nice illustration of this process by Heather Holm, noted bee expert. (We reformatted it here, but you can find the original of this poster on Heather’s website, here.) Click the image to see it larger.

So, What About Those Bee Houses?

Let’s reiterate that Wild Ones Oak Openings Region chapter strongly recommends the use of the natural methods referenced above to help native bees.

Two of our Honorary Wild Ones Directors are noted experts on insects and their relationships with plants. Below are short video clips of presentations in which Doug Tallamy and Heather Holm address the pros and cons of using bee houses.

So that’s what the experts say. But since manufactured bee houses/hotels have proliferated in the marketplace, you may be tempted to use them. They’re often cute garden accents bought on a whim, we get it. But if you’re going to do this, there are some important cautions about using these kinds of bee nesting structures so they don’t do more harm than good. When you encourage large numbers of bees to nest in close proximity, you provide an easy way for pathogens to spread, for example. So, here are some tips to help you help the bees live healthy and productive lives, whether you buy a pre-made bee house or make your own.

• Use hollow tubes in lengths of 6-8″. Tube diameters should vary because different species like to use different sizes — try a mixture of tubes of 6-8 mm diameter (about 0.25 – 0.3″). Make sure the inside of the tube isn’t clogged with anything. Some good options are paper (not plastic) straws or pithy stems from the garden (like asters, sunflowers, bee balm, etc.)
• Rather than making large houses with hundreds of tubes, make a few smaller ones and hang them some distance from each other.
• Don’t glue the tubes together because you’ll need to remove and replace any used ones each year to prevent the spread of pathogens that can kill the bees.
• There should be a solid back on the bee house so that the back ends of the tubes are closed.
• Include some sort of roof that overhangs the front by a few inches to protect it from rain.
• Hang the house(s) so they face the east or southeast and will be warmed by the morning sun. Make sure each house is mounted to a solid structure so it won’t blow in the breeze.
• If you’re building your box from wood, use only untreated wood. You can also use milk cartons or large pvc pipes as the frame to hold the bee nesting tubes.

For more detailed tips on building a safe solitary bee house, visit https://xerces.org/sites/default/files/2018-05/12-015_02_XercesSoc_Nests-for-Native-Bees-fact-sheet_web.pdf