[From Peonies, by Allan Rogers, p. 6-7:] Not all peony species and cultivars are fragrant, but those that are can be classified by which of five distinct odors... rose... A whiff of honey is frequently given off by those flowers with bright yellow central petals... The tang of lemon is confined to the tree peonies... The fourth scent, described variously as sweet or yeasty, is usually found to some degree in suffruticosa tree peonies... Some can only be characterized as unpleasant, sometimes referred to as soapy, bitter, or even medicinal. This quality is usually associated with pollen-bearing cultivars, the red-flowered single forms of which seem to be the worst offenders... the full double Paeonia lactiflora cultivars, sometimes referred to as Chinese or French peonies, may be counted on to possess in varying degrees a pleasing fragrance, stronger in pinks and whites...