I had no idea about this

Peony plants, like any other garden plants, will show signs when they are in need of additional nutrients. If your peonies exhibit stunted growth, fewer blooms, or yellowing leaves, these could be indicators that they require fertilization. Additionally, if the blooms are smaller than usual or the plant appears generally lackluster, it may be time to consider feeding them. It’s important to observe these signs early, as timely intervention can help restore the plant’s vigor.