Cardamine graeca (Brassicaceae), an unexpected new weed in Western Europe?

Cardamine graeca L. (Brassicaceae), a non-weedy species from rather natural habitats in Southeastern and Eastern Europe, was recently found in two cemeteries in Belgium (Genk and Gent). It is suggested that this species most likely has been introduced via the container nursery industry although it is not officially known as such.