Cottage Q&A: Got ants in your plants?

How do you stop ants from eating and destroying potted or basket flowers (potato vine) without hurting the plant?—Sandra, Muskoka, Ont.

The ants are likely attracted to your potato vine plants because there are already aphids feeding on them. These small insects use their sharp, stabby mouthparts to pierce the plant’s leaves and stems and suck out the sap; ants, in turn, eat the honeydew (a sweet, sticky substance) that the aphids excrete as waste after their meals. Ah, nature. So disgusting.

Ants “farm” aphids. Like ranchers with their cattle, “ants protect their aphids and move them around,” says Douglas Justice, the associate director of horticulture and collections at the UBC Botanical Garden. The aphid herd—er, colony—can grow quite large and, therefore, can support a lot of ants. Get rid of the aphids, and you put the ant farmers out of business. They should have no reason to hang around your potato vine plants anymore. There are lots of plant-safe tricks to try, but the simplest is plain old water.

“A good heavy spray will take off most of the aphids,” says Bob Osborne, the owner of Corn Hill Nursery in Cornhill, N.B., and the author of Hardy Roses: The Essential Guide for High Latitudes and Altitudes. Keeping the soil moist will also mitigate the ant impact. “Ants don’t cause direct damage to the foliage, but if their nests are in the soil, this can dry out the roots,” says Obsborne. He suggests soaking the infested plants about once per week.

You should know that while ants are unsightly on a potted ornamental, “in the garden, they’re a good thing,” says Lorraine Johnson, the editor of Canadian Gardener’s Guide. “They’re crucial for moving the seeds of many native plants.” And if you’ve been reading this magazine, you know that in cottage country, native plants are the best kind of plants. No offence, potato vine.

Evict carpenter ants from your cottage with these expert tips

This article originally ran in the Aug/Sept 2020 issue of Cottage Life magazine.

Got a question for Cottage Q&A? Send it to answers@cottagelife.com.

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