How to Plant and Grow Peonies
Perennials keep coming back year after year. Peonies are a perennial and clumps have been known to go through their annual cycle for well over 100 years. The peony family (paeonia) is characterized by large showy flowers and upright plants (even shrubs) with long stems coming up from tuberous or thickened roots.
When selecting a place to plant peonies look for a spot of ground that gets 6-8 hours of sun daily. Try not to get them too close to woody plants because peonies don't compete well with the root system of trees and bushes for the available resources. Also avoid planting clumps closer than three feet apart to allow each clump the best access to soil nutrients.
The best time to plant peonies is in the fall season. Get the soil ready by making sure it is well-drained and has been worked with thoroughly rotted compost to a depth of about 12 inches. As the roots (and roots are what you will be planting) of the peony are of fair size you will want to dig a fair sized hole (8 inches wide by about 12 inches deep). Dig the hole so that most of the buds appearing on the root will be about 2 inches under the soil when covered over. Deeper buds may not flower.
Next cover over the roots and tamp the soil lightly to get rid of air pockets that might allow the plant to dry out. Then be sure to soak the soil with water. Roy Klehm of Song Sparrow Farm in Garden Gate Magazine recommends mulching them over with several inches of straw or oak leaves for the winter to keep the peonies a bit warmer, giving them a better start in the spring. (Be sure to remove the mulch in spring.)
The first year the blooms will be rather weak and the stems short, but the second year they will be stronger and by the third year the established plants, given proper care, will be filled out and robust. Peonies reach their full dimensions in eight to ten years. Over time you will want to fertilize every other spring with a 5-10-5.
Unlike bulbs, peonies can be left in the ground undisturbed for years. They may benefit from division after ten years. This process should be done very carefully. Begin digging eight to ten inches away from the base of the clump. The peony roots can be separated with a sharp knife. Try to arrange it so that each new division has five to eight eyes. You will want to make sure to keep the divisions moist and out of the sun to avoid drying out.
So, what is it with peonies and ants? In some varieties the blossoms become covered with scurrying ants just before they open. The blossoms secrete a nectar that attracts the ants. Some people believe that the ants are necessary to open the tight blossom, but scientific experimentation has shown this not to be the case. Nevertheless, the ants seem not to be harmful (no need to spray them) and will generally leave the plant once the blossom has opened.
Peonies are beautiful for perennial beds and borders. They come in many varieties and colors (except blue). If you have a nice flower bed with a bit of extra space, consider the peony.