It’s disconcerting to many gardeners when peony buds swarm with ants. Although it’s tempting to spray pesticides or repel the small insects with organic remedies, the ants do little harm and may, in some cases, benefit the plant.
The tough, green petals surrounding the bud, known as bud scales, produce a nectar rich in carbohydrates and amino acids. The ants take advantage of this food source until the bud opens and the scales no longer produce the nectar.
Ants defend their territory and may drive off harmful insects.
Contrary to the common myth, peonies do not need ants in order to bloom. Peonies without ants bloom just as fast and as heavily as a similar peony with ants. The ants may, however, repel insects that would otherwise dine on tender peony growth, benefiting the overall plant.
Ants leave the peony plants when the plant stops producing buds. The buds will not attract ants from neighboring yards, and are not a magnet for every ant in the neighborhood; homeowners simply notice the ants when they’re on the highly visible buds.