Let’s start with a little background here: according to the Illinois Department of Natural Resources, there are an estimated 400 to 500 native bee species in Illinois. If you’re anything like I was when I first learned this incredible information, you’re probably wondering where they nest, what they eat, and how to help make space for them so that they can thrive...
Pictured from above: "Bee branches" with drilled holes, and "bee bundles" made from recycled materials.
Well, you’re in luck! We have a lineup of design ideas you can follow when creating your new native garden or editing an existing one. The two groups we'll be focusing on here are cavity nesting bees and ground nesting bees.
First up, let’s talk about cavity nesters —those solitary species that use the hollow stems of plants, empty beetle holes in dead tree branches, or in my case, the nail holes in my east-facing upstairs door frame.
What do they need? For starters, warmth and sunshine. I visited a wonderful gardener last year who had hung bee nesting houses (with replaceable bamboo straws) on a hot south-facing brick wall — and boy, were those houses busy!
What else do they need? To stay dry. Like the little leaf-cutter bees that found my back door the perfect home, there was a pretty hefty overhang that kept the area out of the elements.
What else? Well, because these little guys come in all shapes and sizes, so should the openings in which they nest. If you’re drilling into an old tree branch (like the “bee branches” pictured above from a downtown rooftop pollinator garden), vary the diameter of the holes and the depth at which they are drilled —once you figure out who is there, you can create a colony by drilling the same hole sizes in one block or branch.
Have a bundle of Echinacea stems you cut back from the garden? Try gathering them up in an old tin can and securing it in a protected sunny spot as a kids' project (pictured from a park district kids' camp activity).
Wondering what else some of these bees need to complete their nest? The delicately veined leaves from some plant species work especially well for leaf-cutter bees to trim their tiny round patches from. Cercis canadensis (redbud) and Rubus odoratus (flowering raspberry), among others, come to mind. And yes, there are still all the stems from last year’s garden, so leave many of those up too.
Pictured above: Melissodes bimaculatus (two-spotted longhorn bee) female in a ground nest cavity, and the males huddled together for their nighttime nap.
And now, on to the ground nesters! This group is particularly exciting to think about, as they make up around 70% of the 400 to 500 bee species native to Illinois, and they exhibit some really fascinating behaviors. Pictured above is the super cool Melissodes bimaculatus (two-spotted longhorn bee) in a nesting cavity just big enough for the female to fit, positioned within a colony of other females waiting to emerge (pictured is the Melissodes female from the same downtown rooftop garden project as the “bee branches” above). This species is one of my favorites, and they show up in early July for about a month —all in black, with the males huddling together at night to sleep.
What do these and other ground nesters need? Bare soil, for one. So, though we talk about packing in plants to fill the space and outcompete weeds, some open areas are great too. Not just any stretch of the garden will do, though.
Like cavity nesters, many of these bees prefer it hot and dry, maybe even with silty soil (no mulch!) and no roots to get in the way. Last year, I met a gardener working on a parkway, and as we went to dig in to add some more Sporobolus near the corner, we noticed a good-sized colony of what looked like cellophane bees. This ideal spot was right next to the street, west-facing, super hot, with dry fine soil.
You can incorporate these habitat features into an ongoing design element in your garden by outlining them with stones or edging if you like, or keep them more natural in appearance.
A few last things I’ll mention about ground nesters, and some things I learned from a recent researcher's talk, are that flower resource location is important too. If you’re looking to attract specialist bees, make sure to include their flower species within close proximity to your “bee berm” or dry sunny spot.
Also, these bees may be philopatric —meaning that new generations of colonies have a tendency to return to the same nesting spot year to year. So if you start a colony, keep it up year after year!
Add signage if you want to draw additional attention, especially if the area is out of the way enough to avoid drawing damaging behavior.
We are just getting started in understanding what these incredible bee species need in our garden spaces, so now is the time to experiment and have some fun, be wowed by the incredible force of nature, and see what works in your garden. And if needing some inspiration, just check out these adorable little bee butts below!
(Video by Ellie Nitu --an awesome native gardener!)
Want to share a bit about the bees you’re seeing in your garden? Please share —we’d love to hear from you!
See you in the garden soon!
Liz