Fertilizing and Weeding the Peonies
Peonies must be fertilized during the winter months. There is no rule to the amount of usage of each element (Nitrogen, Phosphorus, Potassium), because this depends on the nature of the soil. Peonies flourish best on soil with a pH from 6 to 7.
During the winter season chemicals against weeds can be used as well. It is important to do this during the cold season, because then the roots are at "rest" (dormant). Otherwise the roots are apt to absorb the chemicals which will cause damage to the peony.
When the young root starts growing in spring several kind of preventive fungicides can be used. This can be persisted until two weeks before harvesting.