Ground bees are common across Michigan, especially in spring when dozens or even hundreds of small bees can suddenly appear nesting in bare patches of lawn. These are native solitary bees, not aggressive colony insects, and they’re active for only about six to eight weeks before disappearing for the rest of the year. Understanding what you’re looking at can save you from destroying some of Michigan’s most valuable pollinators.
Common Ground-Nesting Species in Michigan
Several groups of native bees nest in the ground throughout Michigan, and you may encounter more than one type in your yard at the same time.
Miner bees (Andrena) are among the most abundant. They’re diverse, mostly active in spring, and many specialize on particular flowers. Surveys of Michigan blueberry farms found andrenid bees were some of the most common visitors to blueberry blossoms, and most of the pollen recovered from their bodies was blueberry pollen.
Cellophane bees (Colletes) get their name from the cellophane-like material they use to line the cells inside their nests. Like miner bees, they nest in the ground and often show up in large numbers in spring.
Sweat bees come in two common forms in Michigan. Green sweat bees are small, metallic-colored bees that appear in spring and summer. Some nest in logs, others in the ground. Dark sweat bees are easy to overlook because of their small size, but they’re both abundant and diverse. Sweat bees tend to be the most common group of bees found around Michigan farms.
Squash bees are solitary ground-nesters that exclusively visit squash and related crop flowers. If you grow zucchini, pumpkins, or summer squash, these bees may be nesting nearby and pollinating your garden before you’re even awake in the morning.
Bumble bees also nest in the ground, though they choose abandoned rodent burrows or insulated cavities rather than digging fresh tunnels. Unlike the others on this list, bumble bees are social and live in small colonies.
What Their Nests Look Like
Ground bee nests are easy to spot once you know what to look for. Each entrance is a small hole in the soil surrounded by a conical pile of excavated dirt, almost like a tiny volcano. These mounds can be mistaken for ant colonies. Each nest belongs to a single female bee, but solitary bees often build their nests near each other in large aggregations. Hundreds or even thousands of individual nests can cluster in the same patch of ground, which can look alarming even though the bees are operating independently.
These bees prefer loose, exposed soil on south-facing slopes because those spots warm up earliest in spring. Thin or bare areas in your lawn, garden edges, and sandy patches are prime real estate. If your yard has compacted, heavily shaded, or consistently wet soil, ground bees are far less likely to set up there.
Why They’re Not a Threat
The buzzing activity around a ground bee aggregation can look intimidating, but these bees pose very little risk. They are not aggressive, they rarely sting, and their venom is weak. Most of the bees you see flying low over the nesting area in early spring are males searching for mates, and male bees cannot sting at all. There’s no mass attack response like you’d get from honeybees or yellowjackets. Each female is defending only her own small nest, and she has little motivation to sting unless you directly handle her or step on her.
Ground Bees vs. Yellowjackets
The most important distinction to make is whether you’re seeing ground bees or yellowjackets, because yellowjackets also nest underground and are genuinely aggressive. Ground bees are fuzzy. Their bodies are covered in fine hairs that collect pollen, and they have a stocky, rounded appearance. Yellowjackets are smooth and shiny with sharp black-and-yellow banding and a narrow, defined waist. Behavior is the clearest giveaway: ground bees fly slowly near the soil, entering and leaving individual holes, and show no interest in your food. Yellowjackets are attracted to meat and sugary drinks, fly aggressively, and all enter and exit from a single hole leading to a shared underground nest.
If you see many bees using many separate holes, you’re looking at a solitary bee aggregation. If you see many wasps streaming in and out of one hole, that’s a yellowjacket colony, and caution is warranted.
Their Role in Michigan Agriculture
Ground-nesting bees are critical pollinators for Michigan crops, particularly blueberries. Research from Michigan State University found that native bees like sweat bees and miner bees visit blueberry flowers alongside managed honeybees, and during cool weather, native bees are better able to fly and pollinate the crop. This matters in Michigan’s unpredictable springs, when cold snaps can keep honeybees grounded.
Native bees are also more efficient at pollinating certain crops because they’re better at shaking flowers to release pollen. Having a diversity of pollinator species on a farm spreads risk across many bee types, reducing the chance that a stretch of bad weather wipes out pollination for the season. The ground bees nesting in your lawn may be the same ones pollinating nearby blueberry fields, apple orchards, or your own vegetable garden.
Do They Damage Your Lawn?
Damage to lawns from ground bees is usually minimal. The small soil mounds can look messy, especially in a large aggregation, but the bees aren’t killing grass or undermining the soil structure. Their tunnels actually aerate compacted ground, which benefits root growth. The nesting activity lasts only a few weeks, and the mounds settle or wash away with rain. Control is rarely necessary unless the bees are in a high-traffic area where people walk barefoot or children play on the ground.
How to Discourage Nesting in Specific Areas
If ground bees have chosen a spot where they’re genuinely in the way, the simplest solution is water. Ground bees prefer dry soil, and running a sprinkler over the nesting area will encourage them to relocate. If they return to the same spot year after year, watering that area before they emerge in spring can prevent them from settling in at all.
Growing thicker turf also helps. Because these bees need bare or thin soil to dig into, filling in patchy areas with dense grass or ground cover removes the habitat they’re looking for. Mulching garden beds and reducing exposed soil around your yard makes those spots less attractive.
Chemical treatments are unnecessary and counterproductive. Pesticides applied to ground bee nests kill pollinators that benefit your garden and the broader ecosystem. Since the bees are only active for six to eight weeks and pose almost no stinging risk, the simplest approach is often to leave them alone and let them finish their short season.