Wisconsinites can’t grow 10-foot crotons or poinsettia trees like they do in Jamaica. And our season is barely long enough to get bougainvillea to bloom, much less climb to become a living fence like it does in Arizona and Mexico.
But we can grow peonies, a reward for enduring Wisconsin winters. In fact, peonies need a prolonged winter chill to break dormancy and grow well. Temperatures must be below 40 degrees Fahrenheit, but can be much colder. Peonies are hardy to –50 degrees, making them one of the best perennials for cold climates.
Peonies are one of few flowers that can be called voluptuous, bearing spectacular bowl-sized blooms. Double-flowering types especially can be so top-heavy that they flop under their own weight unless supported. Peonies are in the midst of their magnificent early summer display, sporting satiny pompons in red, light pink to deep rose, white or pale yellow. They’re an old-fashioned favorite that is easy to grow.
Peonies inhabited our family farm before I did, created an informal hedge between our lawn and a field. My mother cut a single stem bud and placed it in a vase. My sisters and I crushed ants that escaped. The next day, as if by magic, the round bud burst open, filling the room with beauty and a sweet scent.
Peonies are attractive throughout the season. Burgundy foliage emerges early in spring, growing into large, glossy, dark green leaves. These shrub-like plants grow to three to four feet tall and wide. Some turn deep purple in fall before dying back.
They often live 50 years or more. Think of planting a peony as a lifetime commitment. And don’t do what I did.
My mother gave me a peony clump one fall, which I stuck in a new flowerbed as a holding area for winter. I had planned to put roses in this new bed, not peonies. But winter brought the wisdom of realizing my mother’s peonies would have much greater long-term sentimental value. So I kept them. The first year, they emerged but did not bloom. I did some quick research and learned that planting depth is critical to peony flowering. The growth buds, the dark red “eyes” at the top of the roots, should be planted about 1½ inches below the soil surface – no more than two inches. Planting deeper will eliminate flowering, or buds will turn brown and never open.
I assumed I planted them too deeply. Reading that peonies should be planted in fall, I dug up my peony so I could plant at the proper depth in autumn. The growth eyes actually were at just about the right depth. As I dug the peony, I severed thick, tuberous rhizomes, made only minor adjustments and replanted it.
Foolishly, I did this and then read more. Peonies develop an extensive root system that can take a couple of years to establish. It’s not unusual for blooming to be sporadic or delayed until year three or four. The important thing is not to disturb them because peonies do not respond well to transplanting.
To help you avoid my mistakes, here’s what else I have learned about growing peonies:
For the best flower display, plant them in full sun in a fertile, well-drained site. Peonies grow best where they do not have to compete with grass or trees for water and nutrients. They prefer good air circulation and protection from strong winds.
- Dig a deep hole, about 24 inches wide and 18 inches deep. Work in compost or organic matter. By preparing the planting hole several weeks in advance, the soil will have time to settle. Plant between Sept. 1 and Oct. 30 in central Wisconsin. If you’re planting from a division, wash off soil and identify the growth eyes to assure planting at the proper depth. If planting bare root, the eyes should be obvious. Container-grown or field-potted plants can be planted any time during the growing season. Carefully check that the eyes are not deeper than two inches.
- Mature peony roots are large and intertwined, so dividing them is a challenge. First cut leaves and stems to the ground. Dig deeply, taking care to lift as much of the root system as possible in fall. Use a sharp knife to make divisions so each has three to five bud eyes. Those with less than three buds will take several years to produce an abundant flower show, writes Mike Heger in his “Growing Perennials in Cold Climates.” Those with more than five eyes tend to live off stored food reserves and do not produce a strong root system.
Large, full double-flowering peonies may be the most popular, but several other forms are available. Single, Japanese, anemone, bomb and semidouble peonies vary in the number of outer petals and central mix of petals or pollen-bearing stamens. These are herbaceous peonies, the common, shrub-like form. Also hardy in central Wisconsin are tree peonies, which grow to five or six feet and bloom earlier.
- Peonies are susceptible to several fungal diseases, notably Botrytis blight. Known as gray mold, it is a problem especially during wet springs, according to University of Wisconsin Extension specialists. Symptoms include sudden stem wilt and collapse or leaves, stems and flowers covered with a mass of spores or young buds turning black and drying up. It can also cause irregular brown lesions on the leaves. Remove and destroy (don’t compost) any affected plant tissue to prevent over-wintering. The mold over-winters in the soil and can survive for several years. Fungicides can be effective if sprayed weekly, starting at bud formation.
- When peonies die back in fall, cut the plant to the ground to control disease problems.
Ants are attracted to sap-like secretions produced by flower buds. While they are common on many cultivars, the presence of ants does not enhance pollination, nor does it harm the plant.
- Peonies are fine fresh-cut flowers. To ensure good flowering next year, do not cut more than one-third of the blooms on any one plant, Heger recommends.
This year, my peony – finally – is loaded with blooms.
– Nick Schultz, Portage Co. MGV
- Frequently Asked Questions (About Peonies) — on the Heartland Peony Society webpage
- Growing Peonies — Ohio State University Extension Fact Sheet HYG-1241-94
- Popular Peonies! — North Dakota State University Bulletin H-281