I had no idea about this

There are certain times when fertilizing peonies is not advisable. Avoid fertilizing late in the growing season, as this can promote new growth that is susceptible to frost damage. Additionally, do not fertilize newly planted peonies in their first year, as they need time to establish their root systems. Over-fertilization can also be harmful, leading to excessive foliage growth at the expense of blooms, so it’s important to follow recommended guidelines.