Floating primrose - willow
The floating primrose-willow is a perennial aquatic plant native to the American continent. It was imported into France in the 19th century as an ornamental curiosity and has since become established in Belgium, France, Greece, Italy, the Netherlands and Spain. The plant is very fast-growing, being capable of doubling in extent in just three to four weeks. It not only shades out any other submerged plants but alters the chemistry of the aquatic environment, thereby reducing dissolved oxygen levels and disrupting entire freshwater ecosystems. Additionally, it blocks up economically important waterways that are used for instance for recreation, fishing or navigation, causing major economic damage. Given its prolific nature, there is a high risk that it will spread rapidly into further Member States. Once established, the species is difficult to manage. EU-level action therefore includes a ban on sales and any planting or keeping, including in isolated ponds. Furthermore, the rapid eradication of any new populations is required to avoid the excessively high costs associated with its management later on. Where the species has become widely spread, appropriate management measures have to be taken.