I would love to know — how much nutrients does peony need?
The best way to ensure you're giving your plants the fuel they need for growth is by using a nutrient mixture with the perfect ratio of nitrogen, phosphorus, and potassium of 10-10-10!
Obviously, you should fertilize with a ratio of 10-10-10 or the equivalent of 1/4 cup per plant when the new shoots come out in early spring.
Don't worry, this peony plant is pretty easy to take care of! It doesn't need a lot of fertilization, and if you go overboard, it might slow down the flowering process.
I really believe that the N-P-K ratio of 5-10-10 would be perfect for your Bartzella peony!