A peony loves well-drained soil: the soil must not absorb too much water. Peonies don’t like wet roots. In addition, you can’t plant a peony in the spot of an old peony. The reason is that peonies excrete a chemical that prevents other plants in the same soil from growing well. Moreover, you should give the plant enough space: peonies can become pretty big and they don’t like to share their spot.