Red ants might not be the garden pests we believe them to be. If you see them swarming around an unhealthy plant, you will likely be eager to learn how to get rid of red ants in the garden. However, chances are something else caused that plant to lose its vigor. This article explains how to distinguish between ants as pests and ants as friends in the garden, as well as how to control ants when they do pose a problem.
First, it’s important to note that red ant is a general term referring to color rather than a specific species. Just as there are many types of black ants, there are many types of red ants. Some species pose a greater threat in the garden than others. To identify the specific type of ant in your garden, look up ants on your state’s Extension website or contact your local Extension office. This will help you understand both how much of a problem the ants actually are and, if necessary, how to control them best.
For example, the Allegheny mound ant (Formica exsectoides), native to eastern North America, has a distinctive appearance with a red-orange head and thorax but a brownish-black abdomen. These ants eat a wide range of arthropods, making them a beneficial predator in the garden. But they also tend to be very aggressive and will bite if disturbed, so you won’t want them in areas frequented by people, especially children.
Red harvester ants (Pogonomyrmex baratus) also have a painful bite but are nonaggressive. They feed on dead insects and seeds. Most importantly, red harvester ants serve as an essential food source for the threatened Texas horned lizard or horny toad. The worker ants of this species are red to dark brown, a quarter to half an inch long, and have a squarish head and spineless body.
Benefits of Ants in the Garden
Not only do ants typically not cause harm in the garden, but they also can provide benefits to your plants. Here are a few reasons to consider not controlling ants in the garden.
- Ants pollinate flowers. While we often think of winged insects — butterflies, bees, even wasps — as pollinators, ants also transfer pollen as they march from one flower to another.
- Ants are predators. As with the aforementioned Allegheny mound ant, many types of ants feed on insects that cause damage in the garden.
- Ants aerate the soil. Ant tunnels help aerate the soil, allowing for the movement of air, water, and nutrients necessary for strong roots and healthy plants.
Problems of Ants in the Garden
Ant mounds in the lawn can make mowing difficult, and ants on cut flowers, like peonies, can ruin the aesthetic of the pretty blooms (and result in ants crawling over your table). But if you notice significant damage to a plant with many ants crawling around, look closer. You’ll likely find aphids, the true culprits. Ants often protect, or “farm,” aphids in order to feed off their excretion, known as honeydew. Getting rid of the ants will not solve the problem; you’ll want to focus on the aphids themselves instead.
And then there are fire ants. If you find fire ants in your garden or lawn, you will want to take immediate action, as these aggressive, swarming insects have a nasty bite. The red imported fire ant (Solenopsis invicta) and European fire ant (Myrmica rubra) are also invasive, meaning they displace native insects and cause other ecologic (and economic) havoc.
How to Get Rid of Red Ants in the Garden
If you do have problematic red ants in your garden or yard, you have several control methods to choose from. Often, the most effective management of insect pests involves multiple control methods, a practice called integrated pest management.
This simply means that you will likely get the best results by using more than one of the methods below to control red ants. It’s also important to note that because only a small percentage of the ants living in a nest are out and about at any given time, killing just the ants you see will have minimal effect.
1. Homemade ant repellent
The easiest homemade ant repellent involves placing cotton balls with a few drops of essential oil in the area where you want to exclude ants. Good scents include peppermint, cinnamon, clove, tansy, and lavender.
Another option is to blend hot peppers with enough water to create a paste, then spread that around the problem area. Make sure to wear rubber gloves and not touch your face! Both of these will need to be reapplied periodically and after rain.
The effectiveness of homemade ant repellents is a subject of debate, but they are worth a try to keep insecticides out of the garden. Using homemade ant repellent in conjunction with bait (see below) will increase the likelihood of success. Just make sure to apply the bait and repellent separately, with the bait along ant trails and around the nest and the repellent only around the plants or areas you want to exclude the ants from. Bait and repellent placed in the same spot will cancel each other out.
2. Borax or baking soda bait
Treating the nest is the most effective way to get rid of ants, and the easiest way to do this is with bait that the ants carry back to the nest with them. When the ants in the nest ingest the bait, they die. The bait least harmful to other wildlife and humans is baking soda. Of course, the ants won’t find baking soda itself attractive, so you will need to mix equal parts baking soda and powdered sugar. Sprinkle this mixture in areas of high ant activity and reapply as necessary.
You can also make a gel-like bait with equal parts borax and honey or jelly or purchase a boric acid bait. While borax won’t harm most beneficial insects, it can kill spiders and is mildly toxic to other animals, including pets, so take care when using this option.
3. Insecticidal bait
If the homemade methods don’t work, you can always purchase insecticidal ant bait from a hardware store or garden center. These function in the same way as the baits described above. Always check the label to ensure you buy the right type of bait for your situation and handle and apply it correctly. You’ll want vegetable-safe bait for use in vegetable gardens and around herbs and fruit, for example.
4. Liquid insecticide
Finally, there is the option of liquid insecticide. Always remember that any pesticide, even one targeted toward a specific pest, can also harm beneficial insects. Again, choose an insecticide appropriate for your needs (e.g., effective on ants, safe for vegetables, etc.) and follow the cautions and instructions on the label carefully.
Liquid insecticide is most effective when applied directly to the nest. To identify an ant nest, follow the ants and see where they go. Setting out attractive food, such as a greasy potato chip, can make this easier. Once you have found the nest, soak it with an appropriate insecticide. Retreatment might be necessary if you see significant ant activity after the first application.
Although red ants rarely cause significant problems in the garden, they can become a nuisance in some situations. When this happens, you can reach for a simple solution (or two!) to eliminate the red ants efficiently and effectively. Remember to correctly identify the ants and confirm that they cause the perceived problem before exterminating these potentially beneficial insects! You might find that you can happily coexist with red ants in the garden.
Serena Manickam is a freelance editor and writer and sustainable market gardener in rural Virginia. She holds a BA in environmental science and runs Fairydiddle Farm, a small market garden in which she grows no-spray produce and herbs to sell at a local farmer’s market.