The peony is just about the longest-living perennial plant you will ever see. There are two basic types of peonies the herbaceous types and the tree peony.
It would be best to plant peonies at the back of flower borders as they are large plants. In the spring, the peonies have attractive ferny foliage and the beautiful blooms are usually produced in May.
Peonies best thrive in a place that receives at least half a day to a full day of sunshine. If the climate is very hot, then provide some afternoon shade for these plants.
The best time to plant the peony is the early fall but early spring plantings do well also. Make sure to prepare the site well. Dig an oversized hole and make sure that you fill some of it with compost.
The secret of having a successful peony is this: Make sure that the tuber is positioned so that the eyes which are located on the crown are covered with about two inches of soil.
Peonies are picky they do not like to be planted very deeply. If your peonies have stopped producing flowers after a few years, then you should see if perhaps they have sunken too low in their bed. Perhaps they have had too much soil sitting on top...