Impatiens balfourii Hook. f. (Himalayas) – A rare but recently increasing, locally naturalised escape from cultivation. First recorded in 1952 in Baisy-Thy (without further details). Discovered in abundance in an abandoned quarry in Eben-Emael in 1984. However, nearly all recent records are from urban habitats (pavement weed, foot of walls, weed in plantations, etc.). Impatiens balfourii has been recorded in the past years in many of the larger cities (mainly Antwerpen, Brussel and Gent) but also in smaller ones and even in villages. It is obviously on the increase and possibly overlooked or merely neglected elsewhere. Some populations are known since several years and are obviously naturalised. Impatiens balfourii recently also occurred in more natural habitats (especially woodland): for instance in Lembeke, Oelegem and Couthuin.
According to Jäger & al. (2008) plants in cultivation are often hybrids and few is known about their true identity.
References
Blanco Salas J. & Vázquez Pardo F.M. (2014) Impatiens balfourii Hook (Balsaminaceae) actuando como especie invasora en la Reserva Natural de la Garganta de los Infiernos (Extremadura). Bouteloua 18: 100-105. [available online at: http://www.floramontiberica.org/Bouteloua/Bouteloua_18.pdf]
Ilijanic L., Markovic L. & Stancic Z. (1994) Impatiens balfourii Hooker fil. in Kroatien. Acta Bot. Croat. 53: 115-119.
Krippel Y. & Proess R. (2017) Impatiens balfourii Hook. f. (Balsaminaceae), nouvelle espèce subspontanée au Luxembourg ? Bulletin de la Société des naturalistes luxembourgeois 119: 55–61. [available online at: https://www.snl.lu/publications/bulletin/SNL_2017_119_055_061.pdf]
Najberek K., Nentwig W., Olejniczak P., Król W., Baś G. & Solarz W. (2017) Factors limiting and promoting invasion of alien Impatiens balfourii in Alpine foothills. Flora 234: 224-232. [available online at: http://www.sciencedirect.com/science/article/pii/S0367253017332802]
Jäger E.J., Ebel F., Hanelt P. & Müller G. (eds.) (2008) Rothmaler Band 5. Exkursionsflora von Deutschland. Krautige Zier- und Nutzpflanzen. Springer Verlag, Berlin: 880 p.
Schmitz U. & Dericks G. (2010) Spread of alien invasive Impatiens balfourii in Europe and its temperature, light and soil moisture demands. Flora 205(11): 772-776.