At my neighborhood Bunco Night, some friends were talking about how beautifully their peonies were flowering. The hostess had a vase full of them. Back at my house, my established peony looked like this:
Yes, even Master Gardeners can have bad luck with a plant. In case you have peonies that look more like mine rather than my neighbors’, here is an overview of common peony problems that could be affecting them.
Failure to bloom
There are multiple reasons why a peony can fail to bloom. Newly planted peonies may not bloom for a few years. Peony tubers should not be planted more than two inches deep, or in shady or wet locations. Competition from other plant roots, poor nutrition, and late frosts can also reduce or prevent flowering.
This fungal disease is common when weather is cool and wet. Symptoms include wilted, blackened stems, buds that turn black and fail to open, and dark brown spots on leaves. Gray mold will appear on diseased tissue. To control, cut off all diseased parts of the plant when symptoms appear. In the fall, cut the plant to the ground and dispose of all the plant material. Do not compost. A fungicide labeled for botrytis can also be used, but removing diseased plant material is recommended and effective. (My plant had this last year, and it appears that I didn’t do a thorough job of cleaning up!)
This fungal disease is less common than Botrytis blight. Its symptoms include black leathery spots on buds, stems that dry up and appear leathery, and plants that die back to the crown. Diseased material should be removed and destroyed (not composted.)
Contrary to popular belief, ants neither help nor hurt peony flowers. The ants are attracted to a sticky substance on peony buds, but they are not necessary for blooming.