University of Illinois Extension
Help your peonies shine this spring

 

[March 28, 2019] 

Herbaceous peonies are a common sight in many gardens and are some of the most beautiful flowers you will find, says Ken Johnson, a University of Illinois Extension horticulture educator.

Herbaceous or garden peonies belong to the genus Paeonia, which is native to Asia, Europe, and western North America. “In addition to their beauty, they can be quite long-lived,” says Johnson. “Many plants have been growing and flowering for more than 50 years and some plantings have been recorded to be over 100 years old.”

Depending on the species and cultivar, peonies will bloom from late spring to early summer. According to Johnson, “Peonies were traditionally white, blush, pink, and red in color. However, due to breeding efforts, coral, yellow, and patterned peonies can now be found.” In addition to a wide variety of colors, blooms also come in a variety of different shapes. The American Peony Society recognizes six different types of flowers: single, Japanese, anemone, semi-double, bomb, and double.

According to Johnson, if your peonies aren’t producing buds and blooming, there are several different things that could be causing this:

• If you planted/transplanted peonies in the last year or two and they aren’t producing flowers, don’t be alarmed; it can often take two to three years for them to establish and bloom.

• Excessive shade can also lead to poor flower development (peonies prefer full sun, but can take some shade). If this is the case, dig up peonies in the fall and place them in a sunny location.

• One of the more common reasons peonies don’t bloom is that are planted too deeply. The crown of the plant should be no more than two inches below the soil surface.

• Overfertilizing can also reduce the bloom of your peonies. Too much nitrogen fertilizer will cause the plants to produce a lot of foliage and a reduced number of blooms. Established plants with good growth only need to be fertilized every few years, if at all. If you decide to fertilize, do so after they are finished blooming, and use a balanced fertilizer or one with a higher phosphorous content (the middle number on a fertilizer package).

Ants are commonly seen on closed flower buds of peonies, and many think the insects help pry the flower buds open. “Despite the old wives tale, peonies do not need ants to help them flower,” says Johnson. Peonies have glands called extrafloral nectaries on their sepals and floral bracts that release nectar. These are different than the nectaries that are inside of the flower that produce nectar and provide food for pollinators. It is believed that plants have these extrafloral nectaries to attract beneficial insects. The beneficial insects, such as ladybugs and ants, will feed on the nectar and protect the plant from pests, Johnson explains.

To get rid of ants on the flowers before bringing them inside, stick the flowers in some water and swish them around. This should remove most of the ants.

Just like roses and other flowers, it's a good idea to remove flower heads and/or seed pods when plants are done blooming. This will help the appearance of the plants and also prevent the plant from sending energy into producing seeds.

[Ken Johnson, Extension Educator, Horticulture]