CORVALLIS - Peonies celebrate the beginning of summer with exquisite silky blossoms and striking foliage. Once established, these beauties are easy to care for, relatively pest-free, and incredibly long-lived. Because peonies can live for 50 years or more, it is wise to give them a good start.
Joyce Schillen, Oregon State University Extension Service Master Gardener, offers some hints on establishing and caring for peonies.
First, choose a site with full sun. In a hot summer climate, such as in southern or eastern Oregon, late afternoon shade is an advantage. Provide shelter from strong winds that may knock over the top-heavy blossoms.
Plant peonies in deep, rich, well-drained soil with generous amounts of organic matter added. Space plants two to three feet apart in masses, or three to four feet apart when used as specimen plants.
After flowering, scratch in a complete, slow-release fertilizer and be careful not to disturb the roots. Water peonies adequately during dry spells, giving them at least one inch of water every week.
Peonies form rounded clumps two to three feet tall. Peony blossoms may be single, semi-double, or double, and come in a range of colors from white to pink to deep, dark red. The foliage dies back to the ground in winter and emerges again in early spring looking like red asparagus.
Ants are frequently found on peonies, attracted by the sweet, sticky substance that is exuded from the buds. While they do no harm themselves, they can carry spores of fungal diseases from one plant to another.
The best control against diseases is good sanitation, according to Schillen. Remove flower heads after they have shattered, but before seed heads form. After the first killing frost, cut stems back to the ground and remove any weeds encircling the plant.
Clumps expand gradually and can be left alone for many years, although they may be divided to increase your plantings. To divide peonies, lift plants in early fall and separate the fleshy roots into segments with a sharp knife. Each segment should have three to five eyes.
Replant them with eyes facing up and exactly one inch below the soil surface. Deeper planting reduces or prevents blooming.