Backyard Gardener: Peonies are an old favorite

Hello Mid-Ohio Valley farmers and Gardeners. Here on the farm it is always around Memorial Day that my grandmothers’ peonies are blooming. Most garden peonies grow two to three feet tall and mature plants may be three to five feet wide. Peonies bear three to six-inch diameter, fragrant flowers around this time of year (late May or early June). They are a beautiful cut flower.

In the gardening world, we are experiencing a renaissance of heirlooms. The garden peony is the perfect heirloom plant; long lived, tough and adaptable. First, this gorgeous bloomer is a hardy perennial. In addition, once it becomes established it is a low maintenance plant and will flower for many years. It is not unheard of for plants to bloom nearly 50 years. They are extremely hardy and can easily withstand winter conditions here in the valley. They thrive in the northern states because they require a cold period as part of their life cycle.

Peonies are considered a great perennial border plant because they produce good foliage and flowers. They have been used for decades as cut flowers for use in the home or on cemetery plots. I can still remember as a young child taking these flowers to the graveyard for decorations. Peonies can be used as single specimens mixed among other plants but are typically planted in clumps or masses. They may be planted in rows forming a background for smaller plants.

There are basically two forms of peonies: Garden or herbaceous (Paeonia lactiflora) and Bush or Tree (Paeonia suffruticosa). Most gardeners seem to have much greater success with growing the herbaceous forms rather than the tree form. There is nothing more spectacular, however, than a mature tree peony in full bloom, and if the plant hasn’t been used in the landscape, it should be given a try.

The herbaceous peonies are grouped into five types based on the shape of the petals: single, semi-double, double, Japanese, and anemone. The single (or Chinese type) is characterized by one row of broad petals that surround a cluster of yellow pollen-bearing stamens. Some of the other flower types have central petals in the place of stamens.

The semi-double peonies have broad central petals. The double peonies have central petals that are as wide as the outer ones. Japanese peonies have long, thin, central petals, while the anemone type have broad central petals.

Tree peonies produce many flowers on single, shrub-like plants. The centers of the flowers are yellow, pink, or red with the petals mottled at the base. Contrary to the herbaceous peonies, which die down in the fall when freezing weather arrives, the stems of the tree remain alive all winter.

There are numerous varieties available within the various types of peonies. By careful selection, the flowering period can be spaced out over a longer period of time. Garden peonies come in an assortment of colors including white, yellow, cream, pink, rose, and deep red. If you are interested in heirloom varieties ‘Baroness Schroeder’ (white), ‘Felix Crousse’ (red), ‘Festiva Maxima’ (white double with a crimson center), ‘Sarah Bernhardt’ (apple blossom pink), and ‘Teresa'(pink) are a few to try.

The best time to divide and plant peonies in the valley is September. Planting later may not allow enough time for the plants to become established before winter. Peonies need be planted in a well-drained location. Wet soils will invite disease issues. They also thrive in high organic matter soils. This may require adding compost, coarse sphagnum peat moss, well-rotted manure, or other similar material to the soil before planting.

Light is also very important. Peonies need full sun to dazzle us with their blooms. The plants will grow and produce good foliage in shady locations, but the flowering will be sparse or non-existent. Select an area that receives sunlight at least 6 to 8 hours per day. Planting where there is good air movement will also reduce the chances of having disease problems.

You can order bare root peonies from nurseries or divide from a neighbors planting. When dividing peonies, cut the stems near ground level. Carefully dig up the plants and wash or gently shake off the soil. Divide the clump into sections making sure that each section has three to five eyes (buds) and a portion of the root system. Divisions with fewer than three eyes may take 3 to 5 years to produce flowers. Purchased roots should be similar with three to five buds. Do not let roots dry out. Plant immediately.

Prepare the site by digging a hole about a foot deep and two feet across. When planting, position the peonies so that the eyes are 1 to 2 inches below the soil surface. This is most important because planting too deeply will inhibit flowering. Fill the remainder of the hole with soil amended with compost or peat moss and water thoroughly. Water regularly during the first fall and spring of establishment. Peonies should be spaced about 3 to 4 feet apart.

Mulch newly planted peonies with several inches of straw in late fall. Mulching will prevent freezing and thawing of the soil that may heave and damage young plants. Remove the mulch as growth resumes in the spring. Take care when removing the mulch as the new shoots will be brittle.

In the spring when the plants start to grow and the shoots are three to four inches high, apply a complete fertilizer such as 10-10-10. One application of fertilizer per year is generally adequate to maintain good plant growth and flowering. Peonies often become a bit top heavy when in full bloom, with the clump splitting down the middle if a heavy rain occurs. This is encouraged by over fertilization.

Have patience. Peonies may not bloom the first spring. In fact, it is advisable to remove flower buds that develop the first spring to promote root and foliar growth. Once completely established, full flower production should continue for many years. Ants are frequently associated with peony flowers. They neither help nor hinder flowering. Ants are attracted to the sweet nectar produced by the peony flower buds.

Remove the spent flowers (deadhead) to improve the plant’s appearance and prevent fruit formation. Fruit development reduces the amount of food the plant is able to store in its root system and may result in fewer flowers the following spring. If peonies become crowded, division of the clump is recommended. Dig the plant and separate the tubers being sure each one has three to five buds. In general, peonies usually do not need to be divided for 10 to 15 years. Contact me with questions at the WVU Extension Office at 304 424 1960 or at jj.barrett@mail.wvu.edu. Good Luck and Happy Gardening!

Question of the Week: What can I do for cabbage worms?

This is the time of year we normally start seeing damage from cabbage worms. The imported cabbage worm is usually the first cabbage worm species to appear and is a fuzzy, elongated green worm. Larvae come from eggs laid by the white butterfly often seen flitting around the plants.

Early control is essential to reduce injury. Bacillus thuringiensis (BT) and spinosad are effective organic products that are labeled for this pest. BT can be found in Dipel©, Thuricide ©and other similar materials. Direct sunlight deactivates BT quickly so it is helpful to spray late in the day or on a cloudy day. Spinosad is the active ingredient in Captain Jack’s Dead Bug Brew© and other similar products.

Conventional insecticides such as carbaryl (Sevin©), malathion and methoxychlor are also effective but will kill natural enemies of these pests. Be sure to hit the underside of leaves where insects feed. Note that hitting the underside of leaves is easier when using a dust applied with a duster than when using a liquid spray.


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