I was trying to add a species (latifolia) name to an iris cultivar, 'Mont Blanc'
English Iris (Iris jacquinii 'Montblanc') and when I did, I got the "The plant you're trying to change this to already exists!" message. When I clicked on it, it takes me to just the species iris itself.
English Iris (Iris jacquinii)
I never had problems with this before if there was a cultivar name in place.