Ask a Master Gardener

Photo of a white flower on a peony plant.

Growing Peonies


It seems like everyone’s peonies look so nice this year. I would like to get some for my garden, but I don’t know anything about them except they are beautiful. Can you help? SD

My first exposure to peonies was in my grandmother’s yard growing up. I don’t remember much about them except that she had probably a half dozen. They grew pretty big (at least they seemed big to me at the time) and that they had these huge flowers. Years later, when it came time for us to sell her home, I re-homed one of her peonies in our yard. Several years later, it continues to thrive. In fact, the photo you see here is her peony that is currently in our yard. But, enough about me…let’s talk about peonies.

Peonies are a perennial plant that does really well here. They actually appreciate a good cold winter and need the temperatures to get below 40 degrees to help them break dormancy in the spring and bloom. In reality, they can take more cold than that, as they are able to survive winter temperatures down to minus 50 degrees. Let’s hope we never experience that here in Oklahoma.

While they are native to Europe, Asia, and Western-North America, they have been grown and cultivated in Asia for more than 2000 years. The cultivated varieties made their way to the United States somewhere around 1800. Longevity is a big plus with peonies since they can continue to grow and flower for more than 50 years. Some varieties persist for 100 years. That’s a good plant investment in my book.

Peonies are in bloom right now, making them one of the earlier spring bloomers. Typically, peonies have been white, red, and pink, but creative breeders have created new varieties in coral, yellow, and a few patterned ones. You can expect a healthy peony to grow to about 2 to 3 feet tall with a spread of between 3 to 4 feet.

When trying to decide if a peony or two is right for you, remember, they like well-drained, loamy soil. Well-drained soil will help minimize potential root rot and fungal disease issues. If you soil leans more toward high clay content, amend the soil with compost or organic matter to improve drainage.

Also know, that newly planted peonies tend not to bloom for the first couple of years, as they need to get well established and comfortable in their new environment before thinking about blooming. If after this period of time, you are not getting blooms, odds are they need to be moved to a location that gets more sun. They prefer full sun, but don’t mind a little shade. But, if you do need to move them, remember, it’s likely another two years before they start blooming.

Peonies are also a little particular on how deep they are planted. When planting, make sure the crown of the plant is not more than two inches below the surface. When they are planted too deep, you get robust foliage, but very few blooms.

Over-fertilizing can also inhibit blooms on your peonies. Your plants will look green and healthy, but they won’t produce blooms. They only need to be fertilized every few years and then only after they are done blooming.

They don’t have a lot of insect or disease issues, but they are susceptible to powdery mildew. Powdery mildew will first show up as small, white spots. But these spots can quickly expand, making the entire plant look like it was dusted with flour.

To minimize issues with powdery mildew, plant them in a place that allows for good air flow and don’t crowd them together. If you suspect your peony is falling victim to powdery milder, begin a treatment program with a fungicide such as copper fungicide. Also, cutting the dead stems back to the ground at the end of the season and removing this plant debris will help to minimize chances for powdery mildew.

Some of you have heard that you need ants on your peony buds to help them bloom. This is not correct. Ants are attracted to peony buds because these buds have something called extrafloral nectaries on the leaf-like petals that surround the flower before it opens. These nectaries excrete nectar before the flower blooms. The nectar attracts ants. Once a hungry ant finds this delicious nectar, they of course go tell the others, leading to the potential of a large quantity of ants returning to your peony for a tasty treat.

It’s also possible that the presence of ants on these buds helps to deter other less beneficial insects such as thrips which wouldn’t be a terrible thing. But, ants are not necessary for you to have blooms on your peonies. All you need is sun, good soil, and a couple of years to get started. See you in the garden!

You can get answers to all your gardening questions by calling the Tulsa Master Gardeners Help Line at 918-746-3701, dropping by our Diagnostic Center at 4116 E. 15th Street, or by emailing us at Photo: Tom Ingram