Ant hills in cracked soil, courtesy of Zoran Milosavljevic
We love keeping ants, and love observing ant behavior in controlled environments, but when it comes to ant hills popping up unexpectedly in your backyard, it's can be a different story different story. Unchecked ant colonies can become a nuisance and certain species can sting children.
Here’s a comprehensive guide for fellow ant enthusiasts on how to responsibly remove ant hills from your backyard while considering the well-being of these fascinating creatures.
Table of Contents:
1. Identifying the most common types of ant hills in your yard
2. Ways to Control Ant Hills
Ant Hill Identification
Most ant species in Canada do not make large ant hills. However, if you do see ant hills in your yard, they will likely be one of the following:
Garden Ants (Lasius spp)
Garden Ants, or Lasius, are small, brown ants that you may see build small mounds over your lawn, and especially in the cracks on your sidewalk. You may see them build small mounds after the rain. Typically, these ants are harmless, and can peacefully coexist with you.
However, if you are an avid gardener, be aware that these ants often protect aphids from predators in return for a sugary substance from the aphids called predators. Left unattended, these aphids can kill your plants. However, they are otherwise safe to you, your kids, and your pets.
Labour Day Ant (Lasius neoniger) worker, Lasius neoniger mound
Black Field Ants (Formica fusca complex)
Field Ants, or Formica fusca complex, are larger, typically black ants which you may see running across your sidewalks. They will build small anthills, and you can identify their nests by the cleared out patches of soil on your lawn.
Unlike what many think, these ants are often beneficial species. They will hunt other pests like mosquitoes, flies, and beetle grubs, and keep pest populations low. However, like Garden Ants, they will farm colonies of aphids which can hurt your plants if they get out of control. However, they are otherwise safe to you, your kids, and your pets.
Field ant worker, Field ant mound
Wood Ants (Formica integra complex)
Wood Ants, or Formica integra complex, often build large mounds, often thatched with pine needles, sticks, and other materials. They can build large complexes of hundreds of nests, and are large, red, aggressive ants. They pack a painful bite, and will spray formic acid (you can identify them partially by the smell of the acid) but are not particularly dangerous to you or your pets.
They are important predators and hunters of other insects, but you may be in for a nasty surprise if you sit on one of their bounds by accident.
Wood ant worker, Wood ant mound
European Fire Ants (Myrmica rubra)
European fire ants will sometimes build small mounds around sidewalks, particularly in humid areas. Uniquely among most ant species you find in Canada, these ants can, and will sting you. You can identify them by their bright red color. Certain field ants are also red and can bite, but they are typically much larger. They're named so because of the itching and burning sensation felt from their stings.
Unlike other ants, European fire ants are also an invasive species, and also harm the environment by introducing invasive plants,
European Fire Ant worker, Fire Ant Warning
We highly suggest trying to remove colonies of this species from your yard.
1. Making Your Backyard Less Ant Friendly
- How it works: Many ant species will move their colonies around based on the conditions in their yard. Often, this means humid patches of grass near rocks, trees, or bushes. Deliberately under watering these areas or otherwise repeated disturbance, like digging up the ant hill, can often coax the ants to move to a different spot.
2. Boiling Water: A Quick Fix
- How it works: Pouring boiling water directly onto the ant hill is an immediate way to collapse tunnels and kill ants.
- Why use it: This method is chemical-free and simple. It can also be repeated if the colony is large or spreads over several mounds.
- Tip: Avoid this near plants or areas where you want to preserve life, as the heat will also damage nearby vegetation.
3. Vinegar and Soapy Water Solution: A Natural Repellent
- How it works: Take a rake and level the ant hill. Then, mix equal parts vinegar and water, and some dish soap and pour it onto the ant hill. Ants are repelled by the strong scent of vinegar. Dish soap will stop the ants from floating to the top of the water, and will drown them.
- Why use it: It’s a safe, non-toxic option for removing ants while being kind to the environment.
- Tip: Though it’s good for small infestations, it may not eradicate the entire colony, requiring repeated applications.
4. Diatomaceous Earth (DE): A Physical Barrier
- How it works: Sprinkle food-grade diatomaceous earth around the ant hills. This fine powder damages ants' exoskeletons, causing them to dehydrate and die.
- Why use it: DE is a non-toxic, pet-safe solution that works effectively without harming plants or pets, as long as you choose the food-grade variety.
- Tip: Reapply after rain or heavy watering for continuous protection.
5. Commercial Ant Baits: Strategic Targeting
- How it works: Place commercial ant baits near ant hills. Worker ants will take the bait back to the nest, killing the colony over time.
- Why use it: Ant baits are effective, especially if you can’t locate all of the nests.
- Tip: Keep baits away from areas accessible to children and pets, as some formulations contain toxic chemicals.
6. Nematodes: A Biological Solution
- How it works: Beneficial nematodes are microscopic organisms that naturally prey on ants and their larvae.
- Why use it: A biological, eco-friendly solution that doesn’t disrupt the local ecosystem.
- Tip: Nematodes take time to work, so be patient. They are a great option if you prefer non-chemical approaches.
7. Essential Oils: A Natural Deterrent
- How it works: Mix peppermint, tea tree, or citrus oil with water and spray it around ant hills. Ants dislike strong scents and will relocate.
- Why use it: This method is chemical-free and adds a pleasant aroma to your garden while keeping ants at bay.
- Tip: Essential oils are more of a deterrent than a permanent solution, so use them to prevent new colonies from forming.
8. Insecticides: Last Resort for Severe Infestations
- How it works: Apply insecticides around the ant hill following manufacturer instructions. These chemicals kill ants and destroy the colony.
- Why use it: When the infestation is too large for other methods, insecticides provide a fast, reliable solution.
- Tip: Use sparingly and avoid disrupting beneficial insects like bees. Be mindful of the environmental impact.
Eradication vs Control
While ants may disturb you and your family, it's usually best to learn to coexist. They play important roles in the environment, and watching their colonies can be great educational opportunities for children. Most ants will leave an area if the environment isn't comfortable for them, and you can often coax them to move somewhere else by repeated disturbance.
When you have ants in your backyard, eradication is usually a last minute and unnecessary resort. But if you do, hopefully this helps.