Great willowherb is a perennial, large (length 50 – 150 cm) herbaceous plant of evening primrose family. The species is often found on the banks of water bodies, in wet lowlands, ditches, on the edges of flooding lowerings, in bogs and forests. They often form monodominant stands and displace less competitive species. In the beginning of the 19^th century the species was introduced in North America and Australia, where it quickly spread over the area and became an invasive species.