Peony Stem Wilt
This poor bud was so close to opening, but unfortunately it was affected by a fungus causing the peony stem to wilt. This stem was infected with botrytis blight which can affect the plant in several ways like stunted growth, Bud Blast, Spotty Foliage, and stem wilt. As you can see from the close up photo below, the infected stem is covered with small reddish black sores or spots. These spots will turn darker as they age and the infected tissue rots. These spots are the evidence of the botrytis fungal disease on the stems. Unfortunately the only thing that can be done for this problem is removal, and the sooner the better. The botrytis blight needs to be removed from the plant as soon as possible to interrupt its reproductive cycle and prevent it from creating spores that will infect next year's foliage. The stem should be pruned back to remove all of the visible blight to just before the next clean leaf on the stem. Once the infected stem segment has been removed from the peony plant, it is imperative that the diseased tissue be removed from the area by trashing it and never composting the infected foliage. Careful, consistent, and timely sanitary practices should improve the health of your plant over time. Good luck!
Close Up of Peony Stem Wilt