Herbaceous Peonies
Herbaceous (or garden) peonies are standard peonies which die back to the ground each year. Old-fashioned peonies like those your grandma grew fall into this category. Often, these plants require support because their stems fall over under the weight of their large, heavy blooms.
Itoh Peonies
Originally developed in Japan in the late 1940s-1950s, result from crossing tree peonies (which have woody growth and are not reliably hardy in Alberta) with herbaceous peonies. These hybrids have a shrub-like growth habit with even larger flowers on thick, self-supporting stems, and do not attract ants, since the buds do not produce sap. Itohs are just as hardy as regular herbaceous peonies, overwintering reliably each year. They produce a woody base and should be cut back to about 6” each fall.