1. Fallopia baldschuanica (Regel) Holub (syn.: Bilderdykia baldschuanica (Regel) D.A. Webb, Polygonum baldschuanicum Regel, Reynoutria baldschuanica (Regel) Moldenke, incl. Fallopia aubertii (L. Henry) Holub, Bilderdykia aubertii (L. Henry) Moldenke, Polygonum aubertii L. Henry, Reynoutria aubertii (L. Henry) Moldenke) (C-As.) – A common ornamental plant in private gardens, increasingly escaping. Most records are relics of cultivation or associated with discarded garden waste. First recorded outside cultivation in 1942 in the sea dunes in Duinbergen (Knokke). At present naturalised at various locations in coastal dunes, usually in vacant lots near residences (Verloove 2002, 2006). Inland locations are more often ephemeral (or rarely locally naturalised near gardens).
Fallopia baldschuanica is a rather variable taxon, especially with regard to flower colour, leaf shape and inflorescence structure. According to Akeroyd (1989) both Fallopia aubertii and F. baldschuanica are in cultivation in Europe, the usual garden plant being the former (characterised by whitish flowers and roughly hairy inflorescence branches). However, on a global scale they appear to be conspecific (Karlsson 2000, Freeman & Hinds 2005, van der Meijden 2005), although the issue surely is not resolved yet (see for instance Anjen & Park 2003).
A hybrid with Reynoutria japonica has been recorded in and described from the British Isles (Bailey 1988, Bailey 2001). It was recently also discovered as seed in Belgium (see under Reynoutria).
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Selected literature:
Adolphi K. (1995) Neophytische Kultur- und Anbaupflanzen des Rheinlandes. Nardus 2: 1-271.
Akeroyd J.R. (1989) Polygonum. In: Walters S.M. & al. (eds.), The European Garden Flora, vol. 3. Cambridge University Press, Cambridge: 125-128.
Anjen L. & Park C.W. (2003a) Fallopia. In: Wu Z.Y. & al. (eds.), Flora of China, vol. 5. Science Press, Beijing & Missouri Botanical Garden Press, St. Louis: 315-318.
Bailey J.P. (1988) Putative Reynoutria japonica Houtt. x Fallopia baldschuanica (Regel) Holub hybrids discovered in Britain. Watsonia 17(2): 163-164.
Bailey J.P. (2001) Fallopia x conollyana. The Railway-yard Knotweed. Watsonia 23(4): 539-541.
Freeman C.C. & Hinds H.R. (2005) Fallopia. In: Flora of North America Editorial Committee (eds.), Flora of North America, vol. 5. Oxford University Press, New York-Oxford: 541-546.
Karlsson T. (2000) Polygonaceae. In: Jonsell B. (ed.), Flora Nordica, vol. 1. The Bergius Foundation, Stockholm: 235-318.
Van der Meijden R. (2005) Heukels’ Flora van Nederland (23e druk). Wolters-Noordhoff, Groningen: 685 p.
Verloove F. (2002) Ingeburgerde plantensoorten in Vlaanderen. Mededeling van het Instituut voor Natuurbehoud n° 20: 227 p.
Verloove F. (2006) Fallopia aubertii. 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: 399.