Peonies are an old-fashioned flower that thrives in our Minnesota gardens. Many peonies have been around for decades and, under the right conditions, continue to thrive and bloom every spring.
There are three types of peonies. Most common is the herbaceous peony, which comes up each spring and dies down to the ground in the fall. Tree peonies grow from woody stems each year and should not be cut back in the fall. The third peony type is the intersectional peony. I had not heard of this one before. It is a crossbred combination of the above peonies that goes dormant to the ground in fall, but has the leaves and blooms of the tree peony. All of the peonies are hardy to Zone 3.
Peonies like plenty of sun and well-drained soil. Mine are in partial shade and continue to bloom, although not as prolifically as they would in full sun. Give them plenty of space so they have adequate air circulation around them. Choose their spot carefully since they can last for decades without splitting or moving them.
Peonies are best planted in the fall following the general rule that spring bloomers be planted in autumn and summer bloomers planted in spring. If purchasing new plants, they will most likely be sold as bare roots. Prepare a large hole with plenty of organic matter. The roots usually have a thick middle piece surrounded by smaller roots with the eyes on the top. Plant the eyes 2 inches below the surface making sure they are pointing upward. Water in deeply. Mulching is also advised to help them through the first winter.
In spring continue to make sure they are well watered, especially for the first year. If flower buds form, only allow a couple to bloom. The plant's energy needs to go into root production the first year. You can fertilize after bloom but they are not normally heavy feeders. When the herbaceous peonies die back in the fall, clean up the foliage to reduce the spread of disease.
Dividing peonies is a cost effective way to increase the number of plants. Sometimes you may want to undertake splitting a plant for sentimental reasons. It is for that reason that I have peonies in my garden from the farm where I grew up. The procedure for dividing peonies is simple, best done when the plant is dormant. Insert your shovel into the soil just beyond the outermost leaves of the clump. Slip your shovel under the clump, too, and as gently as possible try to lift the plant without breaking the tuberous roots. When you have freed the plant, lift it onto a tarp and clip the stems to just a couple of inches. Gently shake the soil from the roots and shower with water. Once the roots are exposed you can start the process of dividing the plant. Using a sharp knife, cut the roots into sections having at least three or four healthy growing buds or eyes. Replant to the proper depth.
That's it, plenty of sun, a little fertilizer, good air circulation. If you take care when planting peonies you'll be able to enjoy their blooms for many Junes to come.
Check the University of Minnesota Extension updated website for help on other questions. Simply type your subject in the search box when you open the Extension page, www.extension.umn.edu. For broader information go to "Learn About" and click on "Yard and Garden." Dial (218) 444-7916 to reach the local Master Gardener voicemail to get help with your gardening problems.