Isosorsimo – Glyceria maxima

The original native range of reed sweetgrass extends from western Europe to central Siberia. It was originally introduced to Finland as a fodder and ornamental plant. As far as is known, it was planted for the first time as early as the 1860s, but particularly towards the end of the 1800s in several locations in Häme and Southwestern Finland. Spreading was initially slow but has intensified in recent decades. Today, reed sweetgrass is common in the silty, clay and muddy shores of lakes and rivers in southern Finland, and in ditches. Occurrences at scattered locations have been reported all the way up to Oulu in the north. The species has spread intensely in the river systems of Kokemäenjoki and Kymijoki. It is abundant, particularly in meadows on the shores of fairly eutrophic regulated lakes, displacing horsetail and sedge growths.

As a vital plant, reed sweetgrass is a strong competitor, which will probably proliferate and expand its range. The species has no natural enemies or stronger competitors in Finland.