Every spring I await the spectacular white blossoms from a single tree peony planted by my mother almost 50 years ago. Family lore says these flowers are notoriously hard to transplant; so I left it alone despite the bruising it gets from growing near the shed door beside a path. That lore was severely tested last winter when my neighbor gave me enough peony crowns for seven plants.
For 35 springs this man and his wife had watched with pride as the gift of his mother-in-law’s peonies bloomed in their back yard. Now the precious heirlooms had to be moved and quickly before the sale of their home. A January evening found him furiously digging in his new yard as many holes for them as he could. Following directions for a deep, well-drained bed, he made 18 holes in the red clay 24 inches deep and 12 inches across. Each hole got a generous helping of composted manure. As the winter sun went down, the precious florae settled into their new home with their tender eyes or growing tips buried no more than two inches deep. When he was out of time and energy that cold evening, I went home with a bucket of bare-root specimens.
A little research revealed the difference between the so-called tree peony my mother planted and the castoff perennial peonies that I placed in a large tub and covered with mulch. Tree peonies are a woody shrub, living as long as 100 years, and the bare branches should never be cut down. The leaves are more dull, but flowers are larger and flatter than herbaceous perennial peonies. Perennial peonies like their cousins are long-lived but die back with the first good frost. The latter grow slowly and can spread 3-5 feet needing that much space between specimens as well.
Once established, with six hours of full sun and little competition from other plants, these perennials require little attention. However, the process of moving can be as traumatic for peonies as it often is for their human caregivers. Our friend had done his homework. Each mass of roots with their tender buds sits just under the surface. Because they cannot stand wet feet, a deep, loose bed is necessary.
I needed more information about caring for these beauties. The genus Paeonia is said to have originated in China where petals have been used medicinally and for tea. Missionary descriptions and Chinese art familiarized Americans with peonies before the plant itself was introduced. It includes both tree or shrub peonies which can reach 6-7 feet in height (sometimes referred to as moutan) as well as the more common herbaceous perennial peonies. They all prefer a slightly alkaline soil and benefit from topdressing with bone meal, compost or an organic fertilizer low in nitrogen. Overfeeding can make for luscious greenery with no blooms. The tree peony particularly may take several seasons to mature enough to flower. The perennials I transplanted made foliage almost a foot high with a few buds in the first spring; but they produced no flowers.
Although they need water, especially early in the season, do not wet the base. Apply water around the drip line. Light shade can be helpful and protection from heavy winds will keep it from losing petals. Staking perennial peonies keeps them from drooping and allows good air circulation. Disbudding, or removing smaller side buds, will encourage a peony to produce fewer large blossoms for cutting. Fall is a good time to apply mulch, keeping the mulch away from the stem to discourage fungus.
Perhaps the most likely problem is botrytis blight in the spring resulting in wilted stalks and blackened buds. Sucking thrip damage can be distinguished from blight by holding a white paper beneath the leaves and tapping the plant. The thrips will fall into the paper. Blight can be treated with fungal sprays on the leaves and/or soil, but remember not to use copper if the temperature is over 85 degrees. Infected plant parts should be cut off and cleaned away as soon as injury is spotted. At the end of the season, rake up dead foliage and discard it to prevent blight from carrying over to the following year.
Dividing peonies is best done in late summer or autumn. The root consists of two parts, a crown from which will come new growth and the many long, thin feeder roots spreading from the crown. Your goal is to cut a pie-shaped segment of the crown with lots of 8-10 inch long feeder roots. Each piece should have 1-3 buds. The trick is to get the right balance of root to top growth. Over fall and winter, the roots are storing food which will be used in spring for growth and flowering. If you must dig up a root with leafy shoots attached, replant promptly providing shade. Either by instinct or the memory of his mother-in-law’s instruction, my friend had dug and divided his roots very well.
Despite initial ignorance on my part, the perennial peonies did well for both my neighbor and me. Waiting for them to mature and blossom is an ongoing challenge. So far the rapacious deer in our neighborhood have not touched them. That in itself is a reason for patience.
References
“Botrytis Blight of Peony,” Mary Ann Hansen, https://pubs.ext.vt.edu/450/450-602/450-602.html
“Perennials: Culture, Maintenance and Propagation,” Diane Relf, http://pubs.ext.vt.edu/426/426-203/426-203_pdf.pdf
“TREE PEONIES,” Jerry Meyer and Leonard P. Perry, http://www.uvm.edu/~pass/perry/trpeony.html
“Care Calendar,” The Peony Garden, Nichols Arboretum, University of Michigan. http://peony.mbgna.umich.edu/care-calendar
Simon and Schuster’s Guide to Shrubs and Vines, Costanza Lunardi, 1987.
http://www.hollingsworthpeonies.com