Abstract
Two non-native Solidago L. species of North-American origin are aggressive plant invaders in most of Europe. Solidago canadensis occurs frequently in most of temperate Europe, while S. gigantea lags behind in north and east Europe. For the first time the distribution and history of expansion of both Solidago species in Latvia were studied and reviewed in maps. The distribution data were gathered mainly in field surveys (2004-2007); other data sources include herbarium materials, literature and unpublished data. Both the widespread S. canadensis and rare S. gigantea are well adapted to a wide range of habitats mostly occurring in human-disturbed habitats in the vicinity of settlements and transportation routes. Over the last century, the dispersal success of goldenrods had been greatly facilitated by land use changes, human alteration of ecosystems, and development of transportation networks.