Several alien species of the Eurasian genus Cotoneaster are naturalising in Central Europe, apparently increasingly so, and some on a massive scale. They presumably originate from large-scale cultivation for ground cover, hedges or as ornamental shrubs. The present paper keys and synopses the Cotoneaster species indigenous to, naturalising or commonly cultivated in Central Europe, on the basis of, relatively limited, both living (wild, adventive and cultivated) and herbarium material. An attempt is made to understand the nature of variation from the genus' centre of diversification, the mountains of China and the Himalayas, which are likewise the origin of most cultivated and naturalising Cotoneaster species. Taxonomic and nomenclatural problems, putatively relating to the presence of apomixis and hybridization in the genus, are discussed. Many of the more than 500 published binomials, including a substantial proportion of those based on cultivated material, seem to be poorly defined, both morphologically and chorologically. Of an estimated total of only 50–70 Cotoneaster species worldwide, about 20, mainly Chinese species have been found escaping from cultivation in Central Europe. Presently, about ten species must be considered fully naturalised and, locally at least, invasive.