Info: Bloom / 03/20/2017 / Windsor Great Park, Windsor, England / License: Creative Commons (cc-by-sa-3.0) (Attribution, ShareAlike)
Caption: photo [as R. aganniphum var. aganniphum] by John Anderson via Trees and Shrubs Online: https://www.treesandshrubsonline.org/articles/rhododendron/rhododendron-aganniphum/