Peonies : Plant them for a lifetime
Peonies are sun-loving, long-lived perennials which are extremely hardy and easy to grow and maintain. Keep in mind that they develop into three foot tall and three foot wide plants which tend to droop when laden with flowers. They are best situated near the middle or back of full sun borders or beds.
Herbaceous and tree peonies.
The common herbaceous peonies die back to the ground each season and while shrubby "tree" peonies have a woody stem system which is exposed to the rigours of winter. The herbaceous variety is divided into common and fern leaf types. Of most interest to gardeners are the common peonies whose flowers are grouped by bloom form: single, semi-double, double, anemone and Japanese. It can be hard to decide which ones to grow, especially when you are trying to choose between all the shades of white, pink, red and coral.
Tree peonies (Paeonia suffruticosa) are a shrubby form of peony with woody stems. They have beautiful, large red, purple or yellow flowers and are hardy through Zone 4 (USDA Zone 3). Tree peonies may be a little more difficult to establish but are well worth the effort. We've grown them for the last five years with no trouble before this past winter when one died - but them so did lots of other perennials. They bloom about 10 days before the herbaceous peonies. Plant them such that the graft is 8 to 12 inches below soil level (that means a deep hole!) This deep planting helps assure your tree peony stays as a tree peony and does not revert to a herbaceous form from the root stock.
Choose peony cultivars for early, mid and late season bloom.
The bloom season for peonies ranges over a period of 4-5 weeks. Early blooming varieties start in late May, mid-season varieties in early June and late season peonies bloom in the last part of June.
When should I plant peonies?
Potted peonies bought at nurseries can be successfully planted any time during the growing season. Early fall is the proper time to dig and divide peonies in your garden. We order our bare-root peony stock for delivery in late August. We will gladly special order peonies that we do not usually stock from our supplier for you.
Where will peonies grow best?
Think sun when choosing a site for your peonies. While they will tolerate light shade, they will bloom better in full sun. Peonies prefer rich, well-drained soil. They thrive in our heavy clay soil. Choose a site where they won't have to compete with aggressive root systems, such as trees or shrubs.
What should I do to prepare the soil?
Dig the area at least 12 inches deep (18 " is better), loosening the soil, breaking up clods and mixing in composted manure. Peonies prefer neutral to slightly alkaline soil. Mix 1-2 cups of bone meal into the soil that will be below the root system. Fill the hole halfway with your soil mixture and compact this soil before placing the peony.
Peony roots have growing points, called eyes, which should be red or pink and firm. Position the root system so that the eyes are no more than 1 1/2 to 2 inches deep when planted. Finish filling the hole with your soil mixture and water well. Double check when you are done that the eyes have not settled too low; when planted too low, peonies will produce lots of leaves and very few blooms.
If they are potted when I buy them, how will I know if they are planted at the proper depth? Plant the peony at the same level it was growing in the container. If you are buying your plants from a reputable company, they should be potted at the proper level.
Keep the ground cultivated and mulched to minimize weed competition. Peonies prefer to be kept moist, but not wet. If possible, avoid getting the foliage wet. After blooming, cut the bloom stalks back, but leave the foliage until it naturally withers in the fall. In the first year of growth, mulching after the ground freezes helps prevent alternate freezing and thawing that can damage the roots. However, we have never mulched peonies and have never had established peonies die from winter stresses.
What type of fertilizer should I use?
Feed peonies lightly each season with a balanced perennial formula, superphosphate or an organic fertilizer. Peonies are not heavy feeders and over-fertilization may result in excessive leaf growth and fewer blooms.
Peonies are easy care perennials.
Most peonies will stay healthy and happy year after year. As with most plants, perennials that are well cared for and properly sited have very few problems. Always clean dead or decaying foliage off the plants, especially at the end of the growing season. Don't put diseased plant material in compost piles - send it to the dump. If you have a problem with disease on your peonies, bring us a sample that shows what is happening and we will be glad to help.
Ants are drawn to the sweet droplets of moisture exuded by the peony blooms. The ants won't do any damage, so why go after them. If you bring peony blooms into the house as cut flowers, dunk the bloom in a pail of water to dislodge ants before bringing them inside..
Why don't my peonies get many buds?
One or more factors may be keeping your peony from blooming well. Most commonly, they are too young, planted too deep, over-fertilized or not receiving enough direct sunlight. Occasionally, an older plant will begin to bloom less and less and may need to be divided and reset.
What causes buds to develop, but the flowers never open?
Buds can be damaged by late spring frosts. We've had this happen infrequently, but it has happened. If the buds open partially and are streaked, check for thrips. Botrytis, a fungal disease, may be a cause later in the season. We've had more botrytis last year than any other year. With botrytis, the buds turn black and fail to open. A gray fungus may develop on stems, or stems turn black and wither . Black leaf spots may appear, especially in a damp, cool season. Immediately cut off affected leaves, buds and stems and dispose of them in your dump garbage- never put the diseased material in a compost pile as the fungus can be easily reintroduced to your gardens. Spray with an appropriate fungicide (Botran, Captan, Daconil 2787 are available products) emerging peony plants in spring if there was a problem with botrytis blight the year before. But use these fungicides grudgingly and carefully they are not nice chemicals to the environment.