Rosa rugosa in Finland
Rosa rugosa (Rosaceae) is native to East Asia and is an established invasive alien plant within the EPPO region. The species was first introduced into the EPPO region as a garden ornamental species at the beginning of the 20th century. In Finland, the species started spreading in the natural environment in the 1930s and now it occurs throughout the coastal areas and the archipelagos up to Bothnian Bay (including Aland Island). On the southern coast, the species occurs in the Archipelago of the Gulf of Finland where it invades shorelines. The species invades natural habitat of conservation value in Finland where it outcompetes native plant species. Further spread of the species was assessed on shores of 665 islands within the Archipelago Sea National Park in the South west of Finland between 2017 and 2018. In total, 96 new occurrences of R. rugosa were found with the average size of new stands equally approximately 4 m2. The most common habitat colonised was stone shore (48 populations), but shore meadows were also typical habitats (22 populations). Other habitats where new populations were found include shrub heath and rock outcrops. In total, 301 populations have been found in the National Park. Control measures are being applied to new populations including manual and mechanical uprooting, herbicide treatment and covering plants with tarpaulin. It is likely that these management measures will need repeated applications over a number of years.
Kunttu P, Kunttu SM (2019) New records of the invasive alien Rosa rugosa (Rosaceae) in the Archipelago Sea National Park, SW Finland. Memoranda Society Flora Fennica 95, 81-88.