In spite of fungicides, I have problems with powdery mildew on my peonies after blooming. They are planted in full sun with ample space between plants. Can I thin the stems out to promote more air circulation without harming the plants? They are full and start out healthy and don't need dividing yet.
Mildew on Peonies
Certified GKH Gardening Expert
It will not hurt to thin out the plant, but do so now in spring. These articles will help with the powdery mildew: https://www.gardeningknowhow.com/plant-problems/disease/get-the-cure-for-powdery-mildew.htm, https://www.gardeningknowhow.com/plant-problems/disease/powdery-mildew-homemade-and-organic-remedies.htm