Two North American slug species are reported from three locations in southern Sweden: three records (in 2005, 2014 and 2015) of Ariolimax columbianus (Gould) and one 2005 record of Prophysaon foliolatum (Gould). The record of P. foliolatum is the first for Europe. In all cases it is highly probable or proven that the slugs had been accidentally imported with ornamental plants from North America, particularly salal, Gaultheria shallon Pursh. Salal is collected on a massive scale from the rainforests of the Pacific Northwest, particularly in Canada and Washington State, and exported as green filler for floral arrangements. The harvest, storage and transport conditions seem perfectly suitable for these slugs, which are not synanthropic but live in natural habitats where salal thrives. We point out that these apparently uncontrolled imports might open the door to the introduction of new, non-synanthropic species.