While they mean the plant no harm, the sight of ants parading up and down a peony's vine is an unwelcome one for many home gardeners. Fortunately, there are a few things that you can do to keep an army of ants from enjoying the sweet nectar they crave from your peonies. You can remove the ants safely without causing undue damage to the plant.
Use a homemade mixture to control the ant population. Mix equal amounts of borax and sugar in a container or bucket, then evenly distribute the mixture around the base of the plant. Mix equal amounts of cornmeal and sugar, as an alternative, and distribute the mixture around the base of the plant. (The combination of these materials is deadly to ants when consumed.)
Detract ants from peonies with offensive odors. Sprinkle cinnamon around the base of a peony plant or place sticks of cinnamon gum around the base. Lay mint leaves around the base of the plant, as an alternative, which ants also find offensive.
Get rid of the ants' scent trail. Prevent additional ants from feasting on your peony's nectar by removing an existing scent, which will eliminate them from reaching a flowering vine. Note the path the ants take to get to the peony. Soak a cloth in bleach or ammonia and cover as much of the path as possible.
Plant ant repellents. Geraniums, garlic, chrysanthemums and henbit are natural ant detractors, and they can be very beneficial in keeping ants away from peonies.
Trap them. Create an ant trap from paper. Cut an 8-inch circle from a sheet of paper. Use a pair of scissors to cut a slit along one side of the circle. Cover one side of the circle with petroleum jelly. Place the circle around the base of the peony, jelly-side up. (The ants will get stuck on the petroleum jelly.)