Helleborus orientalis Lam. (incl. hybrids and infraspecific taxa) (Turkey) – A rare, locally naturalized and increasing alien. Probably all records refer to relics of former cultivation or plants established from discarded garden waste. H. orientalis was probably first documented in 1947 from an estate in Wépion (Bois Marlagne) where it was reported as naturalized in several subpopulations. In the past years it has been observed in rather numerous, widely scattered localities. An up-to-date overview of recent observations is presented at waarnemingen.be (https://waarnemingen.be/soort/view/136782). In several places H. orientalis grows in relative abundance and is obviously naturalized (for instance in Rhodesgoed near Roeselare, Nokere park, etc.).
Helleborus orientalis is a member of section Helleborastrum. It is generally believed that all the species in this section can freely interbreed. Plants in cultivation rarely correspond entirely with the wild plant from Turkey. They mostly refer to complex hybrids and are perhaps better referred to as H. xhybridus hort. ex Vilmorin (see also McLewin & Mathew 1996). Plants in cultivation most often have flowers with a predominantly purplish ground colour, a character of subsp. abchasicus (A. Braun) Mathew (syn.: H. abchasicus A. Braun). In Norden three subspecies have been recorded in the wild (Uotila 2001).
Mathew B. (1994) The spotted hellebore Helleborus orientalis subsp. guttatus. New Plantsman 1(3): 181-183.
McLewin W. & Mathew B. (1996) Hellbores: 6 Helleborus orientalis and Helleborus xhybridus. The New Plantsman 5: 117-124.
Schmiemann G. (2000) Helleborus orientalis. Gartenpraxis 3/2000: 22-26.
Uotila P. (2001) Ranunculaceae. In: Jonsell B. (ed.), Flora Nordica, vol. 2. The Bergius Foundation, Stockholm: 227-335.