Lawn ants can be troublesome, especially if you have a distressed yard. A healthy lawn will help fight ant infestations, but a dying lawn in the summertime is far more likely to have problematic anthills. If you have random groups of ants doing their thing in the yard it's fine. They can even help get rid of aphids that harm your grass. The main problem with lawn ants is the hills, which can choke out grassy areas and cause unsightly bare spots. If you spend a lot of time in your yard, or you have kids and pets that do, anthills are also an issue because of the thousands of ants that can be disturbed and erupt from the hill at once.