Sidalcea is a genus of ca. 20-25 species, all native in North America. Some species are cultivated as ornamentals in Europe (Le Huquet 1997). Most belong to the Sidalcea malviflora group (see Clement & Foster 1994), a taxonomically difficult species complex.
In Belgium two representatives of Sidalcea have been recorded but only one posterior to 1950. Sidalcea candida persisted at least between 1920 and 1929 on wasteland in Lambermont.
Additional alien: Sidalcea candida A. Gray (N-Am., garden escape).
Literature:
Clement E.J. & Foster M.C. (1994) Alien plants of the British Isles. BSBI, London: XVIII + 590 p.
Hill S.R. (2015) Sidalcea. In: Flora of North America Editorial Committee (eds.), Flora of North America North of Mexico, vol. 6. Oxford University Press, New York: 319-356. [available online at: http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=130308]
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.
Köhlein F. (1992) Staudige Malvengewächse. Gartenpraxis 5: 8-12.
Le Huquet J.A. (1997) Sidalcea. In: Cullen J. & al. (eds.), The European Garden Flora, vol. 5. Cambridge University Press, Cambridge: 218-219.
Roush E.M.F. (1931) A monograph of the genus Sidalcea. Ann. Missouri Bot. Gard. 18: 117-244.