Is there any scientific proof that marigolds act as an ant(insect) repellent? I’m asking since ants tend to crawl into the home, since the flower garden is close to the house. With high maintenance roses, along with other plants, adding another plant seems like a burden, unless I can justify it to myself(my chiropractor and my aching muscles). I did receive a marigold plant one year, and it seemed that there were fewer ants getting into the kitchen.
I’m not sure if the reduced ants in the kitchen were due to plugging more holes in the walls, closing the door quickly with a quick change of clothes, more diligent cleaning, eating less fruit, or less flowering peonies.
I can see the marigold should be avoided when planting near beans from your guide to companion planting.
Ants are busy at work on the peonies, so I’m afraid the fertilizing and composting will make me pay a prices…unless marigolds actually have some reason to be there.
Evidence that marigolds can repel ants or other insects is lacking. However, chemicals released from the roots of some marigold species are toxic to certain nematodes (roundworms); some nematodes are pests and can destroy plant root systems.
I did not find evidence that any plant is effective in repelling ants, although there sure is a lot of information on-line about what “works”. Several plants, including aster, calendula, catnip, chrysanthemum, common yarrow, garlic, geranium, mint, and tansy, are claimed to repel ants — but where’s the proof? As well, some articles state that sprinkling crushed red pepper flakes, dried peppermint, powdered garlic, cloves or cayenne on ant trails will irritate the ants enough that they will move away. Again, there is no validation in the literature that these plant-derived substances will repel ants.
It sounds like your main concern is to get rid of the ants in your home. They could be coming in from your nearby flower garden, but at my house, they have just started coming in from the driveway area – not even close to my garden (it’s late May).
From the information you provided, it is more likely that the decreased numbers of ants in the kitchen were a result of your plugging the holes in the walls and diligent cleaning. Peonies produce nectar that attracts ants, so if there were fewer flowers one year, and somehow this plant is linked to the ants getting into your house, it could have made a difference. However, note that ants actually help peonies – they keep away pests that would otherwise eat the flower buds. So when you see ants on a peony, this is not a bad thing! (…unless those ants are marching into your house…)
Toronto Master Gardeners does not recommend home remedies for dealing with pests. Here are a few good articles about ants and how to get rid of them:
- The University of California Integrated Pest Management Program’s How to Manage Pests – Pests of Homes, Structures, People, and Pets – Ants highlight that ants are actually good for the garden. They recommend that you avoid planting certain plants next to your house – i.e., those that attract honeydew-producing insects (e.g., aphids, mealybugs, soft scales, whiteflies) and suggest that you keep the space around your house’s foundation free of plants, grass, mulch and other debris, to eliminate nesting sites for the ants. Inside the home, getting rid of the ant’s scent trail by using soapy water, may do the trick.
- Colorado State University Extension’s Ants in the home advises that ants come into homes to seek food and water – so if you make sure that your food is stored properly and that there are no water leaks, fewer ants will be interested in coming inside. It also describes several different types of ants that may be found in homes.
- The University of Minnesota Extension’s Ants in spring and What to do about household ants discuss several different ant species and highlight the importance of determining the species of ant that’s entering the home. They note that baiting may be a reasonable option to use to control the critters. They also suggest that the best permanent solution is to locate and treat the nest with an insecticide — since in order to get rid of a colony, the queen ant must be killed. A professional exterminator would do this type of work, and in some cases, may opt to treat the perimeter of the house with a spray.
All the best in ridding your home of those dastardly ants!