Frequently Asked Questions about Peonies

News Article

Peonies are wonderful landscape perennials.  They are admired for their elegant spring flowers and their longevity in the landscape. Below are a few commonly asked questions about the planting and care of peonies in the landscape.
How and where can I buy peony plants?
Peonies are usually sold as bare-root or container-grown plants.  Bare-root plants (often sold via mail-order) are best planted in late summer or early fall.  Container-grown peonies (often sold from local garden centers) can be planted in the landscape at any time from spring to early fall.
How and where do I plant peonies?
Most peonies require well-drained soils and full sun for best flowering.  Plants need at least six hours of direct sunlight per day and a location with good air movement helps prevent foliar disease problems.  Woodland peonies can tolerate less direct sunlight if planted under deciduous trees.
Common peonies prefer shallow planting depths.  When planting bare-root plants, position the buds 1-2 inches below the soil surface.  Plants that are planted too deeply do not bloom well. Container-grown peonies are generally planted at the proper depth, so transplant them to a similar depth in the landscape. After planting, be sure to water well the first year to establish a good root system.
Are ants really required to get a peony to bloom? If not, then why are my peonies not blooming?
Ants are not required for peonies to flower.  Ants are attracted to the sweet liquid peony buds exude prior to flowering. This can be washed off to prevent ants from visiting the flowers.
Planting too deeply is the most common reason some peonies do not bloom well.  Make sure the buds are not more than a couple of inches below the surface of the soil.  Peonies that were recently divided and/or transplanted do not bloom well for a couple of years while they are establishing a new root system.  Over-fertilization, especially high nitrogen fertilizers applied to nearby lawns, can also prevent peonies from blooming. 
How can I best harvest and preserve my peony flowers for cut flowers?
Peony flowers are harvested for cut flowers when they are in bud, before they open.  Flower buds that are showing color and are soft in the center are at the best stage to harvest for cut flowers.  After harvest, flowers can be placed immediately into vases of warm water for bouquets or they can be stored in a refrigerator for later use. Flower stems that are stored in a refrigerator should be leafless and wrapped tightly in moist paper or clear plastic to keep them supple until needed.  Moist refrigeration allows you to keep peony flower buds fresh for several weeks.  When ready for bouquets, simply remove them from refrigeration, recut the stems, and place in warm water to initiate flower opening.
How can I prevent my peonies from flopping?
Many peony flowers have double or triple the number of petals – making them too heavy for their stems to support.  Therefore, staking the peony stems as they emerge in the spring or as the flower buds are forming will provide the extra support needed to keep the blooms upright.
When can I divide or transplant a peony? 
Late August through September is the best time to divide or move a peony.  This allows the plant a month or more to re-establish a good root system before the onset of winter.  Once established, peonies do not require regular division like some other perennials.  They can remain in the same location for decades.
What is wrong with my peony leaves?
Foliar diseases like leaf blotch and powdery mildew can discolor or spot peony leaves.  Peony leaf blotch (Cladosporium) causes irregular brownish-purple spots on peony leaves in summer.  The powdery mildew fungus (Erysiphe) covers the leaves in what looks like a dusting of white powder.  See photo below.  Once these diseases appear on the leaves, there is little that a gardener can do.  Fortunately, both types of foliar diseases do not typically kill peony plants.  In the fall remove the diseased leaves and discard them to prevent re-infection next year.  Diseased leaves should not be composted. 
Another consideration may be the location of the peonies.  Peonies planted in too much shade frequently have more problems with foliar diseases than peonies in full sun.  

Dusty peony leaves that are infested with powdery mildew
Powdery mildew fungus covers the leaves in a dusting of white powder.

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