The Eurasian species Artemisia vulgaris L. has been reported from the Eastern Cape Province (Stutterheim District) in South Africa since at least half a century. However, examination of relevant herbarium specimens has demonstrated that the South African plant material belongs to a morphologically similar East Asian species, A. verlotiorum. It is included in the South African Alien and Invasive Species Lists as a prohibited species absent in the country. However, judging from available data, in South Africa it has become a locally naturalised weed of cultivated land and apparently is difficult to eradicate. A. verlotiorum indeed is a pernicious weed in many regions of the world, appearing to be much more invasive than A. vulgaris, especially in warm-temperate and subtropical climates. Characteristics useful for distinguishing these two species are provided.