Ground Bees: What Is Nesting in Your Lawn, and Is It Dangerous?

Ground bees or yellowjackets? Read the hole first

This section comes first on purpose. Almost every guide to ground bees opens by telling you to soak the area with a sprinkler, since the bees want dry soil and move on once it is wet. That advice is sound for bees and genuinely risky if the hole belongs to a ground-nesting yellowjacket, which answers disturbance by sending out the colony.

So identify before you act. The insects are hard to see well when they are flying low and fast, but the holes sit still and tell you almost everything.

What ground bees actually are

There is no insect called a ground bee. The name describes a habit rather than a species, and the habit is overwhelmingly normal for bees. Roughly 70% of the world’s 20,000 bee species are solitary and lay their eggs in underground nests, according to The Bee Conservancy.

The hive is the exception, not the rule. Honey bees are unusual, and most people have simply never met the quiet majority. Each female ground bee digs her own burrow, stocks each brood cell with pollen and nectar, lays an egg on it, seals it, and dies before her young emerge. There is no queen, no workers, and nothing to defend.

That last point explains the behaviour. A honey bee or a yellowjacket defends a colony that represents thousands of hours of shared work. A solitary bee has only herself, so fleeing always beats fighting.

Types of ground bees, and which you are likely to have

Mining bees are the ones most people have, and they are the largest group of ground nesters in North America. Most are also oligolectic: a given species collects pollen from only one kind of flower, and emerges precisely when that plant blooms. If your lawn fills with them for three weeks each spring and then empties, that is why.

Sweat bees get their own treatment, because they behave differently around people. See our sweat bee guide for the tiny metallic ones that land on your arm.

Reading the nest: holes, mounds and aggregations

A ground bee entrance is about a quarter of an inch wide, roughly a pencil’s width. It sits in the middle of a low mound of excavated soil, one to two inches across. The mound is fresh loose grains rather than packed earth, and a heavy rain flattens it.

The thing that unsettles people is the number. Dozens of females often nest side by side in the same good patch of soil, which entomologists call an aggregation. It looks like a colony and it is not one. Each burrow belongs to one female working alone, and the neighbours cooperate on nothing. An aggregation is a good address, not an organisation.

Do ground bees sting?

Females can, males cannot, and in practice they hardly ever do. Male bees of every species lack a stinger entirely, since it evolved from an egg-laying organ. The females have one but no reason to use it, because there is no nest full of siblings to protect.

Stings happen when somebody kneels or walks barefoot on an active patch, or picks a bee up. Even then the result is mild. Our bee sting guide covers treatment and the warning signs worth knowing for any sting.

One search term deserves a direct answer. People look for aggressive ground bees quite often, and the honest response is that aggression itself is the clue that these are not bees. A nest that sends insects after you is a wasp nest.

Do ground bees damage your lawn?

No. The burrows are narrow, they run well below the root zone, and the soil brought to the surface amounts to a few grams per nest. Ground bees eat nectar and pollen, so they chew nothing underground.

The causation usually runs the other way. Females want bare, dry, compacted, sunny soil with thin grass cover, so they colonise patches that were already struggling. Treating the bees leaves you with the same bad patch next spring. Fixing the patch removes the habitat permanently.

How long ground bees last

Usually two to six weeks, which is the single most useful fact on this page for anyone deciding whether to act. Most species are univoltine, producing one generation a year, and the adults fly only while their plants are in bloom.

After that the females die, the next generation develops underground through summer, autumn and winter, and the lawn looks ordinary again until the following spring. Doing nothing is a complete solution on a timescale of about a month.

One thing does carry over. Females often return to the patch where they emerged, so a good site attracts bees again the following spring unless the soil changes. That is why treating the insects achieves so little: kill this year’s bees and the same bare ground recruits a fresh set next April.

How to get rid of ground bees

Assuming you have confirmed they are bees, the effective approach is to change the soil rather than to kill anything. Everything below works by removing what the females are looking for.

• Water the area regularly. Ground bees want dry soil, and consistently damp ground is unattractive. Only do this once you are sure it is not wasps.
• Seed or turf the bare patches. Thick grass cover blocks access to the surface, and it fixes the underlying problem.
• Mulch beds and paths. A few inches of mulch does the same job where grass will not grow.
• Wait. Two to six weeks and they are gone regardless.
• Mow normally. Blades pass well above the burrows. Early morning or evening if the flying bothers you.

What does not work

Cinnamon, peppermint oil, citronella plantings and eucalyptus all appear on the pages ranking for this question, and we found no evidence behind any of them. Blocking individual holes with bricks or stones is also ineffective, since a female simply digs around the obstruction.

Insecticide is the worst option on offer. It means broadcasting a product across turf to reach solitary native pollinators that were leaving anyway. It also does nothing about the bare dry soil that will draw the next generation.

Why you might just leave them

Native bees pollinate roughly 80% of the world’s flowering plants, against about a third of the food supply for honey bees. A large share of that work falls to exactly these solitary ground nesters, and many are specialists that no other insect replaces on their particular plant.

They are also under pressure. The Xerces Society estimates that more than a quarter of North America’s 46 bumble bee species face some degree of extinction risk, and all of them nest in the ground. Bombus pensylvanicus alone has declined by nearly 90%. A bare sunny patch left alone for a month in spring is a small thing to give up.

Found something else outdoors? Our visual identification guide covers the common look-alikes. And carpenter bees are the answer when the holes are in wood rather than soil.

Pest control disclaimer. Photo-based identification can help, but it is not always perfect. For dangerous spiders, large infestations, or anything you are unsure about, contact a licensed pest control professional.