Apparently there’s some interest into the current state of peony back crossing. @benedictedefoucaud asked about this (in french) “Bonjour, je cherche des informations sur les back crossing de pivoines pratiqués en ce moment. merci.”

I guess she’s not referring to simply backcrossing a (lactiflora) cultivar to one of its parents which is nothing unusual, but rather to the intersectional crosses between the herbaceous (hybrid) plants and the shrubby ones. By sheer coincidence I just happened to have received an email with some information about this.

EDITED AND REMOVED BY THE MODERATOR AT THE REQUEST OF A HYBRIDIZER KNOWN TO HIM

Of course backcrossing the intersectional cross (usually ‘herbaceous’ x ‘shrubby’) means you could also backcross to the ‘shrubby’ one. Nate Bremer seems to have been successful trying to do just that. The last image is ‘Bartzella’ x ‘Lutea Hybrid’.