Fall is Peony Planting Time

Whether dividing, transplanting or adding new plants to the garden, fall is the ideal time. Peonies are very dependable, long lived perennial plants that have long been outstanding landscape specimens. Their large, showy flowers come in many forms and colors that are eye catchers in any garden during May. The major complaint of some gardeners is that the flowers are so large they get knocked down and ruined by heavy spring rains. Where this has been a problem, the singles or anemone-flowered types may be more desirable.

The type of peony most planted is the herbaceous type, which dies back to ground level each winter and develops new growth each spring. Another type of peony, the tree peony, may also be planted in the fall. Actually this plant is not a tree, but a woody shrub that slowly reaches a height of 4 to 5 feet. It is an expensive and distinctive plant that should be given a choice location. Tree peonies are available in yellow and lavender, colors not well developed in the herbaceous types, which are predominantly available in whites, reds and pinks.

Do not transplant established peonies unless the plants are growing poorly or have failed to bloom. Peonies do not need frequent digging and division. They may stay in one place for 20 to 25 years without apparent harm and have been known to do well in one location for as long as 50 years. It normally takes new plants about three years to become established and start to flower well. When planting or transplanting peonies, the planting depth is quite important. Tests have shown that although peonies may survive, they do not flower when planted at depths greater than two inches. Therefore, if plants have been set too deeply, and flowering has been poor or non-existent, plants should be reset at a shallower level.

Once established, tree peonies should not be replanted unless absolutely necessary. Tree peonies require deeper planting that the herbaceous types. Those available are grafted to roots of a herbaceous species. The point of the graft should be set about four inches below the soil surface. This encourages root development on the woody stem. The herbaceous root survives only until the upper part develops roots of its own to become self supporting.

When transplanting herbaceous peonies, lift the thick, fleshy roots carefully with a spading fork. They may then be cut into smaller pieces with a sharp knife or hatchet. The buds, or "eyes," are usually clearly visible, and each division should contain at least three of them. The smaller the divisions, the longer it takes before the plants begin to flower again. Buds may often appear the following spring, but they do not develop and bloom. This is often a result of transplanting and normal flowering should occur in succeeding years.

Peonies are planted 3 to 4 feet apart so they have plenty of room to develop. A sunny location where they receive at least six hours of full sun each day is preferable. Since peonies may remain in the same spot for many years through soil preparation before planting is important. Dig the soil 10 to 12 inches deep and wide enough so the roots can spread well. Add organic matter to the soil as well as a small amount of a garden fertilizer about ½ cup per plant and mix thoroughly into the soil before planting.

Mulching is not normally necessary for peonies. However, during the first winter after planting, a straw or hay mulch can help prevent heaving during periods of freezing or thawing. Do not mulch with manure, however, as it may stimulate soft growth and increase in susceptibility in diseases.

http://en.wikipedia.org/wiki/Peony