Do Peonies Really Need Ants

By Kathy Conner Cornell VCE Southside Master Gardener My husband and I have a peony growing where we sit in the warmer winter/spring days. It amazes us how quickly it grows once it sprouts out, seems like 6” a day. Right now, the buds have formed but once the buds start to open, here come the ants. He always tells me that the peony needs the ants to bloom. That was not mentioned when I studied the plant in school so I thought I’d check it out.
These peony buds will open and flower with or without ants. Peonies Paeonia are a plant well suited to me. I may be able to talk and write about plants, but I am a lousy gardener as anyone who has seen my gardens can attest. According to Allan Armitage in Herbaceous Perennial Plants, peonies are a favorite because of “cold hardiness, ease of culture and the early blooms”. It is that ease of culture that works for me. They aren’t picky about soil, are drought tolerant and smell so good. I never fertilize them and Armitage warns that overfertilizing will reduce blooming. Did I mention that deer don’t like them. Peonies love the cold. I did not realize until working on this article that zone 7, our plant hardiness zone here in Southside, is as far south as they will grow. Just like lilacs, they need a chilling period. Armitage said that a few cultivars bred for warmer climates, trialed in the University of Georgia test garden, have survived without the chilling period. Fortunately, here in southside we can grow any peony we want. Now about those ants. The Integrated Pest Management Department of University of Missouri states “It is a myth that peonies require ants to bloom. The relationship between peonies and ants is a type of mutualism in which two organisms of different species benefit from the activity of one another. Peony flowers provide food for ants and in turn, the ants protect the blossoms from other floral-feeding insects”. The key words are “floral feeding insects” meaning insects that feed on the flower petals such as thrips, not pollinators. Please don’t use an insecticide to discourage the ants. They will not hurt your peonies. If you want to bring some blooms into the house, turn the flower upside down and gently shake. The ants should fall out or you could gently rinse off the blooms and the ants will crawl out. Try to be diligent about this or you’ll bring ants into the house and you’ll get a pizzy ant lecture like I do!