Campanula portenschlagiana Schult. (syn.: C. muralis Portenschlag. ex A. DC.) (ex-Yugoslavia) – A rather rare but much increasing, locally naturalised escape from cultivation. Probably long neglected. First collected as an escape in Merelbeke in 1990. Soon afterwards recorded in several different and widely scattered locations (but mostly in Flanders). At present Campanula portenschlagiana has become a typical urban weed of pavement, old walls, cracks, foot of walls,… in many cities. In many cases it escapes close to gardens in which it is planted. However, some populations are obviously ‘wild’ and naturalised (found in abundance, for instance, on an old wall in the village of Stalhille). Campanula portenschlagiana always grows on stony, sun-exposed or slightly shady habitats.
Campanula portenschlagiana is still a very popular rock garden plant in Belgium. Its further spread and wider naturalisation is predictable. It is closely related to Campanula fenestrellata and C. poscharskyana (and others) but by far the commoner in cultivation in Belgium. Curiously, in the Netherlands and the British Isles Campanula poscharskyana appears to be the usual escape (Grenfell 1983, Denters 2004).
Selected literature
Denters T. (2004) Stadsplanten. Veldgids voor de stad. Fontaine Uitgevers, ‘s-Graveland: 432 p.
Dunkel F.-G. (2006) Neues oder Bemerkenswertes zur Flora Bayerns – Achillea roseoalba, Orobanche amethystea und andere Funde. Ber. Bayer. Bot. Ges. 76: 151-168.
Grenfell A.L. (1983) Aliens and adventives. Adventive News 24. BSBI News 33: 10-11.
Verloove F. (2002) Ingeburgerde plantensoorten in Vlaanderen. Mededeling van het Instituut voor Natuurbehoud n° 20: 227 p.
Verloove F. (2006a) Campanula portenschlagiana. In: Van Landuyt W., Hoste I., Vanhecke L., Van den Bremt P., Vercruysse W. & De Beer D., Atlas van de flora van Vlaanderen en het Brussels gewest. Instituut voor Natuur- en Bosonderzoek, Nationale Plantentuin van België en Flo.Wer: 219.