Ah thanks!
I usually wait til all the flowers are gone, cut the dead ones off, then fertilize. Make sure not to get any on the leaves and stem. Then, add a little fresh mulch to the soil to stabilize temperature and moisture the rest of the summer. Usually around the beginning of July.
Then, I split them at the first of Sept if they are thick enough and transplant the extras so they have a couple months without frost to lay down new roots.
Thank you @zekepickleman ....I will give it a go....
I have been told that the most important time to fertilize is after the flowers have bloomed because mid summer, they are driving deeper roots and saving up nutrients for the long winter and next spring rebound. Good luck! Peonies are the best!
https://www.bloomingbackyard.com/post-blooming-peony-care/
My algorithm feeding me what I like!