Are you amending your soil with lots of organic material?? I've found that healthy soil promotes healthy plants.

Yes, and fire ants LOVE organic soil. I had a compost pile full of them one year. My friend lives in the country & ordered a truckload of cow manure. He was going to let it compost for a year. When he went to use it, it was one huge fire ant mound.

I hate fire ants.

Get a container of Amdro - sprinkle it around the perimiter of the fire ant hill - no matter it's size. In a few days if they're not all gone, they will be mostly gone and you can treat again. I've had one container for several years. Haven't had to use it but a couple of times. It's VERY effective.
cora

Ditto the Amdro. Easy to use and takes just a pinch.

Thanks. I treated with some natural stuff. Hopefully, it will work. I found out that Amdro is grits treated with poison that is very dangerous, so I don't use it. I especially would never use it if I had children who played in the yard or was of child bearing age. It's listed as a developmental and reproductive toxin.

Here is a link that might be useful: Amdro info

Fire ants do kill termites though.