Black Ant Infestation

Asked May 13, 2019, 1:33 PM EDT

How do I control a black ant infestation (3' x5') in a flower bed at my front door? Normally, I would ignore them but now they have moved where my wife wants to plant annuals Thanks for your help,

Charles County Maryland

1 Response

Ants are a beneficial and necessary part of your landscape, so it is good to leave them alone to do their work for the most part (killing termites--their arch enemy--for instance.) Their tunnels also allow rain and oxygen to get down to plant roots (all good), they bring up deep nutrients in the soil, and they keep down some other insect pests.

If you have a 3 x 5 foot colony, normally you would not even see them, because they would be far below ground. All our wet weather has saturated soils, however, and ants often move up closer to the surface to live to avoid drowning.

If this is a 3 x 5 patch of solid ants, you can try turning the soil with a shovel (should be easy!) to disrupt them and dry out their eggs and larvae (killing them.) They can evacuate quickly. You should be able to plant the next day. Another approach is to leave a hose running with a low flow of water to drown them--and encourage them to move. You'd also have to do this a day or so ahead of planting. You could also try sprinkling with diatomaceous earth (as a pesticide), but this would have to be replaced after each rain.