Как-то я не очень в этом уверен

Листьями больше похож на гибридный пион.

А что P. x smouthii /P. lactiflora x P. tenuifolia/, которая в некоторых странах бывает в культуре? Stern (1946): P.X Smouthii, according to Horticulture Universal, vol. 4, 274 (1843), is a hybrid between P.albiflora (i.e. P.lactiflora) and P.tenuifolia; this plant is sometimes listed in nurserymen's catalogues as P.laciniata. The flowers of P.X Smouthii have a sweet scent and there is usually more than one flower to a stem ; both these characters are inherited from P.lactiflora. It is a charming plant for the garden. P.X Smouthii is a diploid as might be expected, as both the parents are diploids, but it has never borne fertile seed in my garden. This hybrid may have been called after Monsieur Smout, a chemist in Malines, who was a keen hybridizer of plants.

Похоже на P. x smouthii. Видно, что у некоторых не один цветок на стебле.