Pavement Ants in the Driveway: Small Mounds, Big Colonies

Walk down any Twin Cities driveway in May and you’ll probably spot them: small piles of excavated sand pushed up through the expansion joints and cracks. Those are pavement ants, and the mound you see is the top of a colony that can run thousands of workers deep under the concrete.

Getting to know the pavement ant

They’re small, dark brown, about an eighth of an inch, with fine grooves on the head you’d need a lens to see. They nest under slabs, sidewalks, patios, and stoops because the concrete holds warmth and shelters the colony. In early spring you might witness one of their famous sidewalk battles, where two colonies fight over territory in a swirling pile of hundreds of ants. It looks alarming and is completely harmless to you.

When they come inside

Pavement ants follow slab edges and plumbing penetrations into kitchens and basements, usually hunting grease, pet food, and sweets. Homes on slab foundations and finished basements in suburbs like Blaine, Woodbury, and Eagan see them trail along the baseboard from some invisible gap near the floor. A few scouts in April can become a steady trail by June.

Why the spray bottle backfires

Repellent sprays from the hardware store kill the ants you see and alarm the colony. The nest is under concrete where no spray reaches. Worse, some ant species respond to repellents by budding into multiple colonies. The better approach is slow-acting bait the workers carry down to the queen, plus a non-repellent treatment along the foundation that they walk through without detecting. We match the bait to what they’re feeding on that week, since their preference shifts between sugars and proteins through the season.

What to expect, honestly

Baiting isn’t instant. You’ll see ants feeding actively for several days, and it can take one to two weeks for the colony to collapse. Also, killing the colony under your stoop doesn’t stop a neighboring colony from claiming the vacancy next season, so homes with heavy pressure do better on a maintenance schedule than one-off treatments.

Small stuff that helps

• Sweep up spilled birdseed and keep pet food off the garage floor
• Re-caulk where the stoop meets the foundation
• Fix drips at outdoor spigots; ants need water too

If ants are trailing through the kitchen or the driveway looks like a tiny mining operation, we’ll come take a look for free. Ankora covers the whole metro; call (651) 556-2666.