Conservation biologists are concerned that climate change will cause widespread extinctions because limited capacity for migration could compromise species' ability to adjust to geographic shifts in habitat condition. However, commercial plant nurseries may provide a head start for northward range shifts among some plant species. To investigate this possibility, we compared the natural ranges of 357 native European plant species with their commercial ranges, based on 246 plant nurseries throughout Europe. In 73% of native species, commercial northern range limits exceeded natural northern range limits, with a mean difference of ~ 1000 km. With migration rates of ~ 0.1–5 km per year required for geographic ranges to track climate change over the next century, we expect nurseries and gardens to provide a substantial head start on such migration for many native plants. While conservation biologists actively debate whether we should intentionally provide “assisted migration”, it is clear that we have already done so for a large number of species.