The frequency and abundance of invasive alien woody plants were recorded along roadsides and at watercourse crossings in 69.9 % (151/216) of the quarter degree squares in the study area. The survey yielded 101 species of which the most prominent (in order of prominence) in roadside and veld habitats were: Opuntia ficus-indica, Acacia mearnsii and A. cyclops. The most prominent species (in order of prominence) in streambank habitats were: A. mearnsii, Populus X canescens, Salix babylonica and S. fragilis (fide R.D. Meikle). The greatest intensity of invasion was recorded in the wetter eastern parts and particularly in the vicinity of Port Elizabeth, Uitenhage, East London, Grahamstown, Hogsback and Stutterheim. There was relatively little invasion in the central and western dry interior except along watercourses.