“‘Oh, look, look, Magnolia Z . . . oh wow, we gotta walk up to Magnolia zenii, oh wow, wow, wow! Magnolia zenii is out. Oh, all is right with the world, one of the first magnolias.’” — Michael Dirr, quoted in this piece on his retirement from the University of Georgia.
Like so many other rare Chinese plants, Zen's magnolia is endemic to one mountainside in China, the north slopes of Mt. Boa-hua. The interesting story of Magnolia zenii, including details on its introduction, cultivation and propagation, is expertly told by Peter Del Tredici and Stephen Spongberg in A New Magnolia Blooms in Boston (PDF) from Arnoldia 49(2).
Del Tredici and Spongberg mention that the flowers of Magnolia zenii are “extremely fragrant”. I concur, though I wouldn't want to be forced to smell them for a long period of time. A quick drink of the scent is perfumey and pleasant (and as a garden visitor mentioned to me after I suggested he smell them while I was taking these photographs, “wild”), but I found a longer quaff causes the fragrance to be cloying.