Weigela is a taxonomically complex genus of ten East-Asian species. All are cultivated as ornamentals and specific boundaries have become obscure as a result of hybridisation. The group to which the species beneath belongs is sometimes referred to as Weigela florida group (Clement & Foster 1994) and probably the most widespread in cultivation (and as an escape). Hoffman (2007) recently introduced an alternative classification for Weigela cultivars.
Literature
Bailey L.H. (1929) The case of Diervilla and Weigela. Gentes Herb. 2: 38-54.
Clement E.J. & Foster M.C. (1994) Alien plants of the British Isles. BSBI, London: XVIII + 590 p.
Cullen J. (2000) Weigelia. In: Cullen J. & al. (eds.), The European Garden Flora, vol. 6. Cambridge University Press, Cambridge: 433-435.
Hoffman M.H.A. (2007) Weigela - sortimentsonderzoek en keuringsrapport. Dendroflora 44: 87-127.