Peonies do not need ants to bloom. That’s the most persistent myth in backyard gardening, but it’s simply not true. Peony buds open on their own, with or without a single ant present. What’s actually happening between these two species is more interesting than the myth: a mutually beneficial relationship where both the plant and the insects get something out of the deal.
Why Ants Swarm Peony Buds
Peony buds have small nectar-producing glands on their outer surface called extrafloral nectaries. Unlike the nectar inside a flower that attracts pollinators, these glands sit outside the bud and secrete a sugary liquid rich in sucrose, glucose, fructose, amino acids, and lipids. For ants, this is a high-quality, easily accessible food source. That’s why you’ll see them crawling all over buds that haven’t even begun to open yet.
The nectar production is heaviest during the tight-bud stage, right before the flower opens. This is when you’ll notice the most ant activity. Once the bloom fully opens and the nectaries stop producing, the ants lose interest and move on.
What Ants Do for the Peony
The peony isn’t just giving away free food. In exchange for nectar, ants act as aggressive bodyguards. While feeding on and patrolling the buds, they attack and kill small insects like thrips that would otherwise chew into the developing petals and damage the flower before it ever opens. This arrangement, where two completely different species each benefit from the other, is a textbook example of biological mutualism.
The defense isn’t perfect, and peonies in ant-free environments still bloom just fine. But in a garden setting, the ant patrol likely results in cleaner, less pest-damaged flowers. Think of it as a nice bonus for the plant rather than a requirement for survival.
Why the “Ants Must Open the Bud” Myth Persists
The timing is what fools people. Ants arrive when buds are tightly closed, and they leave around the time buds open. It looks like cause and effect, but it’s just coincidence. The ants are there for the nectar, which dries up as the petals unfurl. Peonies grown in greenhouses, in ant-free soil, or in regions with different ant populations bloom identically. The bud-opening mechanism is entirely internal, driven by the plant’s own growth hormones and cell expansion.
Leave the Ants Alone
If you see ants crawling over your peony buds in the garden, there is no reason to intervene. They are not harming the plant. Penn State Extension specifically warns gardeners against spraying insecticide on peonies to remove ants, because the ants are beneficial. Killing them removes the plant’s natural defense against actual pests while introducing unnecessary chemicals to your garden.
The ants won’t damage the roots, stems, leaves, or flowers. They’re not farming aphids on peonies (a common concern with ants on other plants). They’re simply eating nectar and, in the process, chasing off the insects that would cause real harm.
Removing Ants From Cut Peonies
The one situation where you do want ants gone is when you’re bringing cut peonies indoors. Nobody wants ants crawling across a kitchen table. Fortunately, they’re easy to remove without chemicals.
The simplest method is a water soak. Fill a bucket with cool water, submerge the peony stems and blooms completely, and let them sit for 10 to 15 minutes. The ants will float to the surface, where you can scoop them out or let them overflow with added water. Give the flowers a gentle shake afterward before arranging them in a vase.
If you’re in a hurry, a steady stream of water from a garden hose works well too. Hold each bloom upside down and let the water run through the petals for 15 to 20 seconds. For stubborn stragglers, place your cut stems in a vase of water in a shaded spot outdoors for 30 minutes. Without the nectar reward and with nowhere familiar to go, the remaining ants will leave on their own before you bring the arrangement inside.
Cutting Peonies at the Right Stage
If you want the fewest ants on your cut flowers, timing your harvest helps. Cut peonies when the buds are in the “marshmallow stage,” where the bud feels soft when you squeeze it gently, like a marshmallow, but hasn’t started to open. At this point, nectar production is winding down and fewer ants will be present compared to the earlier tight-bud stage. The blooms will finish opening beautifully in your vase over the next day or two.
Cutting in early morning, before the day warms up, also helps. Ant activity increases with temperature, so you’ll encounter fewer of them in the cool hours. A quick shake of the stem right after cutting knocks off most casual visitors before you even get to the water-soak step.