Ground Bees: Why Are There Little Holes in My Lawn Every Spring?

On the first warm days of April, a patch of thin lawn or a sandy bank can suddenly fill with tiny mounds of soil, each with a pencil-sized hole on top, and dozens of bees cruising low over them. It looks like an invasion. It’s actually a nursery, and it’ll be quiet again in a few weeks.

Quick answer: The bees nesting in little holes in your lawn in spring are ground-nesting bees, usually mining bees, cellophane bees or sweat bees. They’re solitary natives: each female digs her own tunnel, about 1/4 to 1/2 inch wide, in bare, sandy, dry soil. They rarely sting, don’t damage turf, and are active for only three to six weeks. You can safely leave them alone. To discourage them, thicken the lawn or mulch bare spots.

What are ground bees?

“Ground bee” isn’t one species. It covers several groups of native bees that dig nests in soil. The Connecticut Agricultural Experiment Station says the ones most often found in lawns are cellophane bees and sweat bees, along with mining bees, which are important pollinators of fruit trees. In southeastern Massachusetts, one of the first to appear is the unequal cellophane bee (Colletes inaequalis), which the University of Rhode Island’s bee lab notes strongly prefers sandy, south-facing slopes.

Most of the roughly 390 bee species recorded in Massachusetts are native, and many of them nest underground. The sandy soil of the South Coast suits them well.

Why are there bees in my lawn?

Because your lawn has what they want: bare or thin patches of loose, sandy, dry soil in full sun. Each female digs a tunnel, builds a few cells at the bottom, packs each with pollen and nectar, and lays an egg. The young develop underground and won’t come out until next spring.

The bees aren’t attracted to healthy turf. Their nests are a sign of sparse grass, not the cause of it.

Do ground bees sting?

Very rarely. The CAES fact sheet says ground-nesting bees “rarely sting, choosing to withdraw from an encounter,” and will only sting if stepped on or cornered. The bees you see zipping back and forth just above the ground are mostly males waiting for females, and male bees can’t sting at all. Kids can play nearby, and you can mow over the nesting area.

How long do ground bees stay?

Only a few weeks. Activity at a nest site usually lasts three to four weeks, according to the CAES, and other extension services put it at four to six. If several species take turns nesting in the same spot, you might see bees there on and off through the summer. Many sites are reused the following spring, because the young bees emerge where they grew up.

Ground bees or yellowjackets?

Count the bees at each hole. Ground bees are solitary: one female per hole, with lots of separate holes close together. Yellowjackets nest in a single underground colony, with many wasps flying in and out of one entrance. Yellowjackets are smooth, shiny and bright yellow, and they’re the ones that defend their nest. If that’s what you’ve got, our post on why yellow jackets get aggressive in late summer explains what to do.

Should you get rid of ground bees?

In most cases, no. They’re short-lived, gentle and useful. The CAES lists more than 80 species of wild bees that visit apple blossoms, and native ground nesters are often more efficient pollinators than honeybees. Pesticides aren’t recommended: they kill pollinators and don’t stop new bees from nesting in the same bare soil next year. Filling the holes doesn’t work either; the bees just dig new ones.

How do you stop ground bees from nesting in your lawn?

Change the soil, not the bees. The CAES recommends:

1. Thicken the turf. Overseed bare patches in fall so there’s no open soil to dig into.
2. Add organic matter to sandy patches, such as compost raked into the surface.
3. Mulch or gravel paths and beds. Bark mulch, pea gravel or a dense groundcover makes bare ground less inviting.

Or give them a spot. A sunny, sandy corner left unplanted can host a nesting site that’s out of everyone’s way. Our guide to pollinator plants for coastal yards suggests flowers to plant nearby.

Frequently asked questions

Are ground bees dangerous to kids and pets?

No. Ground-nesting bees almost never sting unless they’re stepped on with bare feet or grabbed. The bees flying low over the nest site are mostly males, which can’t sting.

Do ground bees make honey?

No. They’re solitary bees. Each female stocks her own few nest cells with pollen and nectar for her young. There’s no colony and no stored honey.

Will ground bees ruin my lawn?

No. The bees don’t eat grass or roots, and their small tunnels don’t harm turf. They choose bare, thin areas that were already struggling. Some extension services note the tunnels even loosen compacted soil a little.

Why do the bees come back every spring?

The young bees spend the winter underground and come out the next spring at the same spot, then nest nearby. As long as the soil stays bare and sandy, the site stays attractive.

Are ground bees the same as bumblebees?

No, though bumblebees can nest in the ground too. Bumblebees are big, fuzzy, social bees that usually move into old rodent burrows as a colony; see bumble bee vs. honey bee vs. carpenter bee. Ground bees are smaller and solitary, with many separate holes.

Sources

• Ridge GE, Stoner KA. “Ground Nesting Bees.” The Connecticut Agricultural Experiment Station fact sheet.
• University of New Hampshire Extension, “Should I be concerned about ground nesting bees in my yard?”
• University of Rhode Island Bee Lab, Colletes inaequalis fact sheet.
• NC State Extension, “Finding Holes in Your Lawn? Could Be Ground Bees.”

Those little sand volcanoes are a good sign: your yard is feeding and housing native bees. Give them a few weeks and they’ll be gone until next spring.