- Photo credit: @Leslie J Mehrhoff
- Myriophyllum herterophyllum
- Common Names: Broadleaf watermilfoil, Various-leaved water-milfoil
- Habitat: Freshwater ponds, lakes, canals, ditches, slow flowing rivers, estuaries, canals, reservoirs and marshes. Can grow on mudflats if water levels drop
- Description: Submerged rooted evergreen fast-growing perennial plant. A popular plant in the aquarium and water gardening trades and can be readily obtained under a variety of names.
- Origin and Worldwide Distribution: Native to the Eastern United States, the broadleaf watermilfoil is a popular plant in the aquarium and water gardening trades and can be readily obtained under a variety of names. In Europe, the species has become established in the wild in Austria, Belgium, Germany, Spain, France, Hungary and the Netherlands.
- Potential or Known Impacts: The broadleaf watermilfoil poses a major threat to biodiversity because of its rampant growth and the formation of dense mats of submerged plant matter through the entire water depth and on the surface. The mats impede the water flow and reduce sunlight and oxygen availability, causing the loss of native species and significant alterations to the ecosystem. It affects all types of freshwater bodies, including wetlands. The risk of the plant spreading into other European countries is high.
- How did it/could it get here? It is a popular plant in the aquarium and water gardening trades and can be readily obtained under a variety of names.
- Is it found in Ireland or Northern Ireland? Not present in Ireland or Northern Ireland.
Static Distribution Map as of December 2019 - Courtesy of CEDaR
- Methods for Prevention: EU-level action includes a ban on sales and any planting or keeping, including in aquaria, as well as rapid eradication of any new populations to avoid the excessively high costs associated with its management later on.
- Current Legislative Position (Listed on 02 August 2017) This species must not intentionally be brought into the Union; kept; bred; transported to, from or within the United Kingdom, unless for the transportation to facilities in the context of eradication; placed on the market; used or exchanged; permitted to reproduce, grown or cultivated; or released into the environment. For further queries, you can contact the Non Native Invasive Species Team in the Northern Ireland Environment Agency on 028 9056 9558.