Selecting Sites for Peonies:
One of the most important thing about planting peonies is that need to be sited in well draining soil as they do not like to have wet feet. They need to be planted in filtered shade in warm climates, if possible, as they will not bloom in full shade and the flowers will have a shorter lifespan when in full sun. Where they are adapted, they can grow for 100 years, and they do not require regular fertilizer or even water in some cases. When I plant my peonies, I add compost and peat moss mixed into the soil at planting time and then neglect them as far as further feeding, unless I am adding a mulch between rows. If you are mulching with shredded paper like newspaper or junk mail, sprinkling on a little nitrogen rich fertilizer over it to help the paper decompose. Do be careful not to cover the roots of the peony with paper or mulch any deeper than it is planted. In California and in other warm climates, the buds are planted just below or at ground level. Do not let fertilizer touch the plant roots or growth or it can burn the peony.
Peonies need lots of water when they are getting established and during the growth period. After they have been in the ground for a few years, they will take some drought conditions but still need water occaionally. They should be watered during the periods when they are growing and blooming. As they will die back and go dormant at the end of the summer, water is not as important after the blooming season is over.
Large, double peonies tend to need staking as the mature plants can get very tall and the weight of the blooms can make the stem flop. There are several types of aids, individual stakes, circular wire with three legs that encircle the plant and put into place as the plant is sending up stalks. Another type has a grid where individual stems are coaxed through the mesh in order to keep them in place. Single peonies need no or less staking than doubles.
No stems should be cut during the first year of a plant’s bloom. When a stem is to be cut, try to leave as many leaves as is possible so that they can manufacture food and the nutrients can feed the roots at the end of the season.
Cutting Back at the end of the season:
The stems and leaves will dry to brown at the end of the growing season and can be cut away or pulled off when dry. These leaves should be removed to a compost pile rather than being left alongside the plants to avoid gettng disease or fungus. In warm climates, they do not need any top dressing or mulching to protect from cold.
Dividing Peony Clumps:
When dividing the roots, leave 3-5 buds on each division and replant with compost mixed into the soil and water well. This is done in the fall.