We don't. The classes listed are based on what the quoted references state it is. While most say that it is a Bourbon or Hybrid Bourbon, the 1895 reference from Journal des Roses believes it is a cross between a Rosa alpina (i.e. pendulina) and a Bourbon.
Best Rose Guide by Phillips & Rix pg. 115 lists synonyms for Zephirine Drouhin as the following: 'Belle Dijonnaise', 'Ingegnoli Prediletta', and 'Mme Gustave Bonnet'
Bug_girl, the description of flat-topped buds came from merging a foundling rose, “Davies Sleep Out Rose” with Zephirine Drouhin. As the petals start to unfold, I did notice they seemed to be all at the same level. (See my photo uploaded 16 Oct 20.) However, I agree that this description of flat topped buds might be a bit confusing and have deleted it.
I'm in US 5b/6a, and have a five-year-old plant of Zephirine Drouhin that has always consistently bloomed with the typical intense cerise color--major spring bloom with spotty rebloom through the summer. This spring I have been amazed at what has happened with my plant. It is sporting all over the place, not just with the candy pink 'Kathleen Harrop' looking sport, but with the much lighter 'Martha' looking sport, some mottled blooms, and some blooms that are darker than KH but lighter than ZD. And there are numerous sports all over the plant! I can't find any information on whether this is typical of ZD when she sends out sports, or if it is unusual for there to be so many at one time? Does anyone have an idea about that?
I'm including a couple photos-one when the blooms were budding, and one since they have opened.
A mottled sport of ZD sounds very interesting indeed. I live in a 5b location nd always supposed I couldn't grow ZD, though I love her dearly, and KH as well.
