Fire Ants in Texas: What Houston-Area Homeowners Need to Know

Fire ant mounds have a couple of distinctive features. Unlike many ant species, they have no visible entry hole at the top. The ants enter and exit through a network of underground tunnels that radiate out from the base of the mound, sometimes extending several feet in every direction.

The mounds themselves tend to be dome-shaped, built from loose, granular soil. Fresh mounds look fluffy and light-colored. Older ones get compacted and darker. You will usually find them in open, sunny areas: lawn edges, garden beds, along driveways, near sidewalks, and around HVAC pads. In wet weather they sometimes relocate, which is why a mound that disappeared after heavy rain often reappears nearby a few days later.

Texas is deep in the heart of the red imported fire ant's U.S. range. The climate in the Kingwood and Spring area, warm winters, high humidity, and clay soil that holds moisture, gives colonies almost no reason to slow down. In most northern states, cold winters kill off a significant portion of fire ant colonies each year. That natural check barely applies here.

Our area also has limited native ant competition to push back against fire ants. Once a colony gets established, it tends to stay and grow. Mature colonies can contain 200,000 to 500,000 workers, and a single colony can have multiple queens in some cases, which makes eradication harder.

Rain is a mixed signal. Heavy rain drives ants to move their brood up toward the surface (which is why mounds seem to erupt after storms), but it also scatters colonies into multiple satellite locations. That scattering is one reason a mound can seem to disappear after flooding but the ants are still on the property.

Pouring boiling water on a mound kills some ants but rarely reaches the queen deep in the tunnel system, and it damages your grass. Individual mound drenches with over-the-counter products (chlorpyrifos or permethrin granules poured on the mound) kill surface workers but the queen retreats and rebuilds within two to four weeks.

The two most reliable approaches for yard-wide control are bait programs and broadcast insecticide treatments, often used together.

Baits work by having worker ants carry a slow-acting insecticide or insect growth regulator back to the queen as food. Because it takes a few days to work, the whole colony gets exposed before any ant recognizes the threat. Broadcast treatments lay down a perimeter that kills ants before they can establish new mounds.

Fire ant stings cause a sharp, burning pain followed by a raised welt that turns into a white pustule over the next 24 to 48 hours. Multiple stings happen fast because the ants swarm and sting repeatedly. Most people experience localized pain and itching. Scratching the pustule increases infection risk, so leave it alone.

A small percentage of people have systemic allergic reactions: hives, swelling away from the sting site, difficulty breathing, dizziness. That is a medical emergency. Call 911. People who know they are highly allergic should carry an epinephrine auto-injector if they spend time outdoors in Texas.

Children and pets are at higher risk simply because they are closer to the ground and less likely to notice they are standing in a mound. Check your yard before kids play in it, especially after rain when mounds shift around.

Year-round control is realistic, but zero fire ants is not a permanent state in this part of Texas. New queens fly and establish new colonies constantly. The goal is to keep populations low enough that the yard is safe.

Quarterly or semi-annual professional treatments, combined with keeping the yard mowed short and removing wood piles and debris where ants like to nest, gives you the best ongoing protection. In spring, colonies grow fastest and treatments matter most.