Crocosmia x crocosmiiflora
Crocosmia xcrocosmiiflora (Lemoine) N.E. Brown (= C. aurea (Pappe ex Hook.) Planch. x C. pottsii (Macnab ex Baker) N.E. Brown; syn.: Tritonia xcrocosmiiflora (Lemoine) Nicholson, Montbretia xcrocosmiiflora Lemoine) (Hort.) – A rare but apparently increasing escape from cultivation or garden throw-out. A very small but stable population is known since at least 25 years (and confirmed in 2009) from a road verge near an old castle in Bellem (Aalter). Further recorded in recent years in several, widely scattered localities. See here for an up-to-date overview: http://waarnemingen.be/soort/view/150819. Locally perhaps more or less established. In the Kempen, for instance, repeatedly recorded in the surroundings of Kalmthout, Mol and Postel. There sometimes seen in rather remote, natural habitats (heathlands).
Crocosmia xcrocosmiiflora is probably only moderately hardy in Belgium and could die back in severe winters. A future naturalization is only likely in climatologically favorable areas, for instance along the coast. Once established it readily behaves like an invasive environmental weed.
Nelson E.C. (1993) Who was the author of Montbretia crocosmiiflora? Watsonia 19: 265-267.
Wijnands P.O. (1986) The correct citation of Montbretia crocosmiflora. Bothalia 16: 51. [available online at: http://www.abcjournal.org/index.php/ABC/article/view/1066]