Step in the wrong spot in a Central Texas yard between spring and fall and you learn fast what a fire ant mound feels like. These are red imported fire ants, an invasive species that has made itself thoroughly at home across the region, including the Highland Lakes. They are aggressive, they sting in groups, and they seem to come back no matter how many mounds you flatten. Understanding why they thrive here is the first step toward keeping them off your property.
Quick answer
Red imported fire ants do well in Central Texas because the climate, open sunny lawns, and disturbed soil suit them, and they have few natural enemies here. They spread by mating flights, budding colonies, and flooding, so spot-treating one mound never ends it. The reliable fix is a two-step approach: a broadcast bait across the whole yard plus treating individual mounds.
Dealing with this right now?
Done fighting fire ants one mound at a time? ACI Pest & Lawn treats your whole yard the right way and keeps after it through the season. Request service and we'll take the mounds off your plate.
See how we handle it on our ants page.
They Are Built for This Climate
Red imported fire ants came up from South America, and Central Texas suits them almost perfectly. They like warmth, they like sun, and they like open ground, which describes most lawns and pastures around Burnet and Llano counties. Our long warm season gives them many active months, and the colonies barely slow down until it gets genuinely cold.
They are also opportunists with the soil. Construction, tilling, mowing, flower beds, and even foot traffic disturb the ground, and disturbed soil is prime real estate for a new mound. New developments and freshly landscaped yards tend to fill with fire ants quickly for exactly this reason.
Few Things Out Here Stop Them
In their native range, fire ants are kept in check by parasites, diseases, and competing ant species that evolved alongside them. Almost none of that came along when they were introduced to the U.S. So in a Central Texas yard, a fire ant colony has very little working against it.
They also muscle out the native ants that might otherwise compete for space and food. Over time a property can shift from a mix of harmless native ants to a fire-ant monopoly, which is part of why the problem feels like it snowballs.
How One Mound Becomes Twenty
The reason flattening a mound never finishes the job is that fire ants have several ways to spread, and the colony you can see is only part of the story. The queen lives deep underground, and if she survives, the mound rebuilds.
Knowing how they multiply makes it clear why a property-wide plan beats chasing individual mounds.
- Mating flights: winged ants leave the mound, mate in the air, and new queens land yards or miles away to start fresh colonies, often after a rain.
- Budding: some colonies have multiple queens, and a group can split off and walk a short distance to set up a new mound nearby.
- Flooding: when heavy rain hits, fire ants can ball together and float, riding water to a new patch of your yard.
- Moved soil: potted plants, sod, mulch, and fill dirt can carry a colony in without anyone noticing.
Why Spot-Treating Fails
Pour something on a single mound and you might kill the workers you can see, but you often miss the queen, and you do nothing about the colonies you have not found yet. Worse, some quick treatments just irritate the colony into splitting and relocating, so you end up with more mounds than you started with.
There is also a timing trap. Mounds get most visible after rain when the ants push up to the surface, which makes people treat then. But scattered survivors and the dozens of small or hidden colonies across the yard mean the population bounces right back. You are treating symptoms, not the population.
The Two-Step Approach That Works
Texas A&M AgriLife has long recommended what they call the Two-Step Method, and it is the most reliable way to clear a yard. It treats the whole property as one problem instead of mound by mound.
Step one is broadcasting a bait across the entire yard. Foraging ants carry the bait back and feed it to the colony, including the queen, so it reaches the part you cannot dig down to. Step two is treating any individual mounds that need faster knockdown, usually the ones near doors, patios, play areas, or anywhere people and pets are at risk. Bait for the long game across the whole yard, mound treatment for the spots you need handled now. Timing the bait for when ants are actively foraging, in mild weather and not right after a soaking rain, makes a real difference in how well it takes.
When to Bring in a Pro
You can run the two-step method yourself, and for a small yard it is worth a try. But fire ants reinfest, the products and timing matter, and a large or recurring problem wears people out. A professional program keeps bait down on a schedule and handles the mounds that pop up, so you are not starting over every few weeks.
ACI Pest & Lawn works the Highland Lakes and the surrounding Hill Country, and fire ants are one of the most common calls we get. We treat the whole property the right way and keep after it through the warm season so the mounds do not creep back into your lawn, beds, and the spots where your kids and pets actually play.