May Plant of the Month: Peonies

Peonies are a historically beloved flower with many examples blooming in Mizzou Botanic Garden beds on the Francis and Carnahan Quads, with others scattered throughout campus.

Thanks to a generous gift from native Missourian, MU alumnus and internationally recognized peony grower and hybridizer, Don Hollingsworth, hollingsworthpeonies.com, visitors to MUBG may view a selection of his introductions. A listing of Hollingsworth peonies and a map with their locations are now available on the website.

You can read about Hollingsworth and his peony-inspired life on the MUBG website.

Herbaceous peonies are those whose foliage dies to the ground in winter and breaks dormancy to reappear in early spring. They first appeared in North America in the 1800s by way of European immigrants.

Most of the herbaceous peonies in gardens are Paeonia lactiflora, a species native to central and eastern Asia. There are many hundreds of registered cultivars and increasingly more hybrids are being bred for improved bloom and plant characteristics that lend themselves to more diverse landscape use. 

Woody peonies, P. suffruticosa, also called tree peonies, are peony bushes that do not die to the ground. This group blooms earlier and often more spectacularly than their herbaceous cousins.

A third group of peonies are the Itohs, which are derived from an intersectional cross between herbaceous and woody species. This difficult cross was first accomplished by Japanese nurseryman Toichoi Itoh in 1948. Hollingsworth, was the first American to successfully make such a cross.

Like its herbaceous parent, an Itoh’s foliage dies to the ground each winter and resprouts in the spring. And like its woody parent, it’s blooms are held aloft above its foliage. Itohs bloom longer than either parent.

Established in 1903, The American Peony Society (APS) is an international non-profit organization and registration authority for peonies. It is an everybody-who-is-anybody in the peony world organization. Hollingsworth has served on the APS board since 1976, twice as its president. He also earned the American Peony Society’s (APS) Bertrand H. Farr Lifetime Achievement Award and A.P. Saunders Memorial Medal.

Peony care:

Peonies require little care but it is advised that diseased foliage and stems be removed throughout the growing season. In fall, remove herbaceous peony stems and leaves, cutting them even with the ground.

Water soil around the drip line of the plant, never the foliage.

If peonies must be fertilized, bulb fertilizers can be used. Avoid products high in nitrogen as they cause soft, disease-susceptible growth. Apply fertilizer around the plant’s drip after flowering and again in late August. Do not use manure. It has been linked to the peony disease botrytis.

Spent blooms may be removed to tidy up plants but foliage should remain throughout summer to photosynthesize in preparation for the following year’s show.