Peonies bloom in a brief but spectacular explosion of flowers each spring and can continue blooming for up to 50 years. The dark green foliage makes a wonderful backdrop for colorful annuals after the Peony blooms are spent. Small wonder they are loved by gardeners.
Peonies send up red shoots in mid to late spring and early summer, depending on the variety. By using a mix of varieties it’s possible to have Peonies blooming for about six weeks. Place supports for the plant after the shoots appear. Peonies will droop from the weight of the heavy flowers, especially when wet from rain. The shoots give way to shiny green foliage. Large, round buds appear next. The buds open to blooms which last about a week.
Peonies are available in a wide variety of colors. Cut bouquets for the house just after the outer leaves of the bud open. Leave as much of the stem and leaves as possible. "Dead head" or trim off any spent blooms to prevent seed production. Spring is also the time to provide organic matter around the Peonies. The University of North Dakota recommends spreading 1 to 2 inches of well-rotted manure, staying 12 inches away from the plants.
Peonies grow during the summer months as the green leaves produce food; however, the growth will be underground as the plant spreads and produces new "eyes" or small red buds. Continue to care for the Peonies by watering and weeding. Take care that the peonies do not stand in water, as the roots may rot. Annuals of various colors may be planted around the Peony to take advantage of the backdrop of green leaves standing 2 to 4 feet high.
Fall is the time to divide the Peonies and prepare them for winter. Newly divided Peonies may not bloom the following spring. The University of North Dakota recommends that any flower buds that do appear should be removed to allow the newly divided plant to produce a good root system. Divide the Peonies only if they have become overcrowded and blooming is impacted, or to share with other gardeners or other garden plots. Most Peonies are hybrids that do not "come true" from seed, so division is the most common method of propagation. Prepare the Peonies for winter by trimming them to a few inches above the soil and removing the cut leaves and stems. Place an inch or two of straw over the plot.
Peonies go dormant in the winter. Most require a period of freezing temperatures. The Tree Peony, Paeonia suffruticosa, can produce blooms in southern areas where winter low temperatures average in the 30s and 40s; however, the leaves must be removed in November to trigger a simulated dormant state. Herbaceous Peonies, Paeonia spp, require a dormancy period with freezing temperatures. They are not recommended outside of zones 2-8 due to the freezing requirement.