NEIGHBORHOOD GARDEN FOR APRIL 7, 2012

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PEONIES

BY GLADYS JEURINK

 

          A Bush Peony is an herbaceous perennial.  Its foliage dies to the ground with frost and needs to be removed. A Tree Peony is woody and should not be cut back. Peonies generally do not grow over three feet tall and wide but I have seen Tree Peonies in Lincoln over seven foot tall and wide. Bush Peonies prefer full sun in order to bloom while Tree Peonies can tolerate some shade to make their blooms last longer. Tree Peonies my bloom as much as 2 to 3 weeks earlier than bush ones.

          The Chinese perfected the Peonies almost a thousand years ago.  All Peonies like well drained, dug deeply soil, to which as much organic material as possible has been added. Since both may remain in the same spot for as much as one hundred years, soil preparation is very important.  Both types are heavy eaters.  Yearly spring addition of a high phosphorous fertilizer is recommended.

          As a general rule Tree Peony flowers are larger and heavier than Bush Peony flowers. Tree Plants can be purchased in spring in pots or other containers, while Bush Peonies are almost always found for fall planting.  Late August or anytime in September is also the best time for transplanting Bush Peonies.  Sometimes you can find Bush Peonies in the spring in pots and it is ok to plant them then.

          Here in Nebraska the pink “eyes” of bush peonies should never be deeper than two inches when planting.  Tree Peonies may be grafted on bush peony roots with the graft about four inches down. Eventually they will develop their own rots.  Trees may take as long as six or seven years after planting to bloom while bushes almost always bloom the second year.

          Both types are very cold hardy, and in fact they do not do well in the Southern part of the United States as they require so many days of cold in order to form flower buds.

          If you are planning to grow from seed, both types may take over a year to germinate.

          Bush Peony blooms are traditionally used for Memorial Day. In a warm spring they will bloom too early.  The almost opened buds can be kept in plastic bags for as long as three weeks in the refrigerator. The night before needing them, bring out of the refrigerator and place in water up to the bloom.  They should open for the next day.

          I have several yellow Tree Peonies. The heads are usually so heavy that the wind or rain can make them flop.

          There is another Peony that is harder to find, more expensive, blooms a little earlier, and never gets as large. It is herbaceous and usually referred to as a ‘Fern Leafed’. The only ones I have seen have smaller bomb shaped blooms and are bright red. They are treated as any other herbaceous plant.

          All are listed in books as Palonia species.  The blooms may be saucer, cup, or bowl shape, or single (5 to 10 petals) and a large central “boss” of stamens, or 2 semi-double with 2 or three rows of petals, or 3 double with large flowers of crowded petal filling the center so that stamens may or may not be present.

          Divide Peonies in the fall or root cuttings in the winter.  Cuttings of Tree Peonies can be taken in summer.  They are long lived plants.  I have seen some as advertised in place for 100 years.

          They are prone to Verticilium wilt, botrytis blight, stem rot, leaf blotch, and Japanese Beetles.

Copyright 2012

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TREATING PEONY DISEASES

BY GEORGE EDGAR

 

          As Gladys indicated above, Verticilium Wilt, Botrytis
Blight, Stem Rot, Leaf Blotch, and Japanese Beatles can be a problem for the Peony grower. The University of Nebraska-Lincoln Extension has a NebGuide #G1620 that is a good resource on Peony Plant varieties, growing Peonies, and dividing Peonies. They also include the few problems Peonies have. “Disease management is most effective when problems are avoided, rather than attempting to “cure” a sick. Plant Disease prevention begins with proper site selection, cultural management, and good sanitation practices. Of these techniques, sanitation, removal and destruction of all affected plant parts, is the most important to disease control. Spent flower blooms and affected buds, should be removed when plants are dry. Pruning tools should be cleaned in a 10 percent bleach solution (1 part bleach to 10 parts water) after cutting diseased plant material before making any cuts to a healthy plant.

          In the fall, cut all stalks to just below the soil surface without injuring the buds....Fungicides should be applied when the new growth is just emerging in the spring, being sure to thoroughly cover all plant parts.” (1)

          I try to remove all plant parts, healthy and diseased, in the fall and remove them from the garden. If unable to like this fall, I do it before the new shoots emerge. I do not put them in the compost pile just in case there are some disease spores present. Then in the spring I apply a copper fungicide such as Bordeaux powder when the new shoots are about 2 to 3 inches tall. A liquid copper spray can be used if desired.

Resources:

1. “Peonies” by Mary Anna Anderson, Dale T. Lindgren, and Jennifer L. Chalky, NebGuide #G1620, Issued April 2006, http//exension.unl.edu/publications

2. “Botrytis Blight” Prepared by Juliet E. Carroll Extension Associate, Plant Pathology, December 1985, revised March 1991 by Diane M. Karasevicz, Extension Associate, Cornell University Cooperative Extension of Schenectady County, Schenectady, NY 12308 www.cceschenectady.org
Copyright 2012