This study provides a detailed analysis of the invasion by Eupatorium adenophorum Spreng (Crofton weed) from Burma and Vietnam into Southern China since the 1940s. Currently, E. adenophorum's main colonisation area is located in the Yunnan-Guizhou Plateau of China, where it has caused prominent economic and ecological problems. Sixty-three years ago, Crofton weed appeared in Menghai county, Yunnan Province, from where it dispersed northwards and eastwards at an average speed of 20 km year(-1). The invasion of E. adenophorum nonetheless showed pronounced variations in both time and space. Spread was relatively slow in the initial invasion period between 1940 and 1950, while the most rapid range expansions occurred in the 1980s. Environmental conditions at native and invaded sites were significantly different, reflecting a great adaptability of the species during colonization. These changes were greater than habitat differences between colonized and many adjacent un-colonized sites in Southern China. Therefore, immediate measures are required to stop a further northward and eastward expansion of Crofton weed.