Ground-nesting bees are common across Maryland, especially in spring when dozens or even hundreds can emerge from lawns and garden beds over a short period. Most are solitary species that pose little risk to people and cause no lasting damage to turf. If you’ve noticed small holes in your yard with bees buzzing low over the ground, you’re almost certainly looking at mining bees or one of their close relatives.
Common Species in Maryland
Maryland is home to several types of ground-nesting bees. Mining bees are among the most frequently spotted. They range from roughly honeybee-sized down to much smaller species, tend to be furry, and are usually darker than honeybees. Some have bright stripes, while others are a shiny metallic green.
Green sweat bees are especially common throughout the state. These small, iridescent bees are easy to recognize by their metallic green bodies. You’ll often see them digging in bare patches of soil and visiting nearby flowers. Other ground nesters you might encounter include cellophane bees and digger bees, all of which share the same basic habit of raising their young in underground tunnels rather than in hives.
When They’re Active
The most noticeable burst of activity typically happens in March, when large numbers of bees emerge from the ground after developing as larvae the previous year. This is the moment most Maryland homeowners first realize they have ground bees, because what was an unremarkable patch of lawn suddenly has dozens of small holes with bees hovering above them.
Adults are only active for a few weeks. During that window, females dig new burrows, provision them with pollen, and lay eggs. Then the adults die off, and the larvae develop underground through the rest of the year, not to be seen again until the following spring. By mid to late April, most of the visible activity is over.
What Their Nests Look Like
Each nest is a small hole in the ground, roughly a quarter inch in diameter. Some bees push up a tiny mound of excavated soil around the opening, creating what looks like a miniature volcano. In a yard with a large population, you might see these mounds scattered across a sunny, well-drained section of lawn, sometimes just inches apart. Despite appearing colonial, each hole belongs to a single female raising her own brood. The bees simply prefer the same soil conditions, so they cluster together.
The holes and mounds are not harmful to your lawn. They don’t kill grass or destabilize soil. The tunneling actually helps aerate compacted ground, which benefits root growth and water absorption.
Sting Risk Is Very Low
Ground-nesting bees are not aggressive. Females can sting, but they rarely do, and their venom is weak compared to honeybees or wasps. You would essentially need to step on one barefoot or trap it against your skin to provoke a sting.
Most of the bees you see flying erratically over the nesting area in early spring are males searching for mates. Male bees cannot sting at all. So the swarm-like activity that looks alarming is actually the least dangerous group of the bunch. If you can walk through the area without swatting at them, they will ignore you.
Should You Remove Them?
In most cases, no. Ground bees are important pollinators for Maryland’s native plants, fruit trees, and vegetable gardens. They’re temporary visitors to your lawn, active for just a few weeks before disappearing on their own. Pesticides are unnecessary and can harm other beneficial insects in your yard.
If nesting bees are in a high-traffic area where small children play barefoot or someone in the household has a bee allergy, the most effective long-term strategy is changing the soil conditions they prefer. Ground bees favor dry, sandy, sun-exposed soil with thin or patchy grass. Thickening your turf by overseeding bare spots, adding a layer of mulch to garden beds, and watering the nesting area more frequently during early spring all make the site less attractive. A healthy, dense lawn with consistent moisture is rarely chosen as a nesting site.
For the current season, simply marking the nesting area and avoiding it for a few weeks is the easiest approach. The bees will finish their cycle and the mounds will flatten with the next rain.
Ground Bees vs. Yellow Jackets
The one situation that does warrant caution is misidentification. Yellow jackets, which are wasps, also nest underground in Maryland. They’re far more aggressive and can sting repeatedly. Yellow jacket nests have a single entrance hole (often an inch or larger), produce heavy foot traffic of wasps flying in and out, and the insects themselves are smooth-bodied with bold yellow and black patterns. Ground bees, by contrast, have fuzzy bodies, create many individual small holes rather than one large entrance, and fly slowly and calmly near the ground. If you see a single busy hole with smooth, fast-flying insects, that’s likely a yellow jacket colony and a different situation entirely.