Do I have bees in my lawn?
Q: There are many piles of soil and small holes appearing in my lawn. Is this from ground bees or ants? How threatening are they to my children and dog that play in the yard?
A: Almost certainly bees; ants would make fewer mounds and the entrance hole wouldn’t be as obvious. Plus, you’ll probably see the adult bees coming and going if you watch for a while. Good news – ground-nesting bees won’t bother people or pets if left alone (teach the kids not to grab them, though), and even most of the ground-nesting local wasp species that some people also call “ground bees” (which aren’t very active yet) will ignore us if we let them go about their business.
Only ground-nesting yellowjacket wasps, which act quite differently than ground-nesting bees and solitary wasps, might warrant concern. Still, yellowjackets and other social wasps are not active to this degree either right now.
April brings us into solitary bee season, when the adults of some species emerge and buzz about in a flurry of activity over the ground. Solitary bee nests are like human housing neighborhoods: individuals have homes in the same general area because the environment is suitable for their needs, but each family unit has its own dwelling. In the case of the bees, each household is just the lone female and her future offspring. The term “solitary” might sound like you’re only going to see one or two, but often there’s a whole colony present.
We encourage gardeners to let ground-nesting bees continue their activity if they find your yard appealing. They’re valued native pollinators, and their choices for habitat dwindle with each patch of land that humans develop or which becomes smothered by invasive species. These bees need soil loose enough to dig in, and prefer open areas (like a lawn) that have some exposed soil they can access. They probably won’t be digging into a mulched flower bed.
This means that, for people who want to discourage them in lawns, the simplest approach is to thicken-up the turf by overseeding and following the other care tips to boost grass vigor in our Lawn Care and Maintenance web pages. As a bonus, these efforts also discourage most weeds from establishing.
Want to learn more about these cute busy bees? Entomologist Mike Raupp has a brief blog article and video about plasterer bees on his Bug of the Week blog and YouTube channel of the same name. This is a commonly-seen group of solitary bees also called cellophane bees because of the weatherproofing liner they apply to the inside of their burrows.
The female bees will only be active for a few weeks, and then all will be quiet again, with the
baby bee larvae tucked away in their burrows until next spring.
Q: We’re taking down our invasive pear tree and want to replace it with something native. What’s something underused that supports wildlife and casts more shade than the pear? A:
I have a fondness for the common hackberry (Celtis occidentalis), the native shade tree with an unwelcoming common name. Finding one to purchase might be challenging compared to widely-grown species like maples and oaks, but as native plants become more popular, underused species are finally getting some exposure.
No species will be pest-free or look spotless all season long, but hackberry handles urban conditions well (compacted soil,
air pollution, limited root space, higher soil pH, and/or reflected heat from the pavement). Sometimes nuisance pests or minor leaf spot infections can disfigure some leaves (a caveat far from being unique to hackberry), but they don’t hurt the tree. A small number of cultivars exist, and some may be resistant to more prominent conditions like witches-broom that can affect twigs.
Three butterfly species use its foliage as a host plant (caterpillar food), and hackberry grows across the entire state in various soil types. Any insect feeding in its canopy or wandering over its interesting corky mature bark makes great bird food, and over twenty bird species can also consume its berries.
Although I’ve heard that the “hack” name might refer to the
hard seed in each not-very-fleshy berry, the Lady Bird Johnson Wildflower Center and other references say that the Hackberry common name derives from “hagberry.” This meant “marsh berry” among Scots using the term for wild cherries in Great Britain. Hackberry doesn’t look like local wild cherries to me (nor does it want to live in soggy soil long-term), but cherries are “stone fruits” with their similarly hard pits, so wherever its name comes from, I think it’s an underappreciated native tree.