By Audrey Stallsmith
Our familiarity with the fable of the ant and grasshopper often makes us hesitant to exterminate virtuously hard-working ants. After all, they help clean up wildlife carcasses and prey on some bad insects. They also aerate soil, spread seeds of wild flowers, and even protect butterfly larvae.
However, ants also protect and “herd” bad bugs such as aphids for their honeydew, not to mention occasionally damaging seedlings and invading houses in search of sweets. To cope without killing, try setting out the following strong-smelling plants that repel ants in or near places from which you wish to exclude those insects.
Although the licorice scent of its seeds has been used to train foxhounds, anise (Pimpinella anisum) doesn’t have the same allure for ants as it has for dogs. Hardy only in USDA zones 6 through 10 and grown as an annual elsewhere, it reaches 2 feet in height with lacy white blooms and ferny foliage. If anise doesn’t succeed in making your ants cry uncle, you still can add its foliage to salads and its seeds to breads and desserts.
Catnip (Nepeta cataria) may be, well, catnip to cats, but definitely is not a mood enhancer for ants. It grows to nearly 3 feet tall and around with musky gray-green foliage and insignificant white flowers and is hardy in USDA zones 3 through 10. However, you might attract every feline in the neighborhood even as you rebuff the ants! If this plant fails as an insect repellant, you always can dry it for your cats’ enjoyment instead—or to brew tea for yourself.
Chrysanthemums deter ants due to the toxic pyrethrins present in the flowers of some of them. The type most frequently used in pesticides is Dalmatian daisy (Chrysanthemum or Tanacetum cinerariifolium). It grows to 18 inches in USDA zones 5 through 9 with ferny foliage and small white blooms. A more colorful alternative is the painted daisy (Chrysanthemum or Tanacetum coccineum), which can reach 3 feet in USDA zones 3 through 7 with 3-inch flowers in a variety of bright hues.
Peppermint or Spearmint
Although a minty-fresh scent might be attractive to humans, it reportedly repulses ants. For this purpose, either peppermint (Mentha x piperita) or spearmint (Mentha spicata) will do. Hardy in USDA zones 3 through 10, these mints generally grow to 2 feet with unobtrusive lavender or pinkish white flowers, respectively. They also can be used for adding a minty flavor to recipes or for garnishing summer drinks. Keep in mind, though, that the plants can be highly invasive if not contained.
Because it also belongs to the mint family, pennyroyal (Mentha pulegium), too, can give ants the royal brush-off. It hugs the ground in USDA zones 6 through 9, generally growing only to 4 inches with blooms ranging from white to pinkish-purple. Although sometimes used as an herb, it has more possibly dangerous side effects than most mints, which can make it a bad penny. So you’ll probably want to let it lie and be a freshly minty penny instead.
The plants that produce hot peppers (Capsicum annuum) also might provide you some protection from ants, since those insects find the chemical irritant capsaicin less than captivating. Since it is present only in the fruits rather than the foliage of peppers, however, those plants probably won’t have any protective capacity until they bear. Varying widely in size and appearance and usually grown as annuals, peppers can be perennial in USDA zones 8 through 12.
Though you might be more familiar with sage (Salvia officinalis) as a Thanksgiving herb, the plant reportedly can repel ants in addition to spicing stuffing. It grows to about 2½ feet in USDA zones 4 through 8 with silvery foliage and spikes of mauve flowers. If its musky scent doesn’t discourage the ants visiting your countertops, you still can dry and grind the plant’s foliage—and use your homegrown sage to impress aunts who visit during the holidays instead.
Probably the most touted ant repellant plant, tansy (Tanacetum vulgare) can grow to 5 feet in USDA zones 3 through 8, with ferny foliage and bright-as-a-button petal-less yellow blooms. Its strong, spicy fragrance reportedly drives away fleas as well as ants. However, the plant is invasive enough to be considered a noxious weed in some states. And, although it has been used as a substitute for sage, it can be toxic if overconsumed.