Identifying Brazilian elodea can be tricky so be sure to get an expert to confirm the species before planning any control measures. The plant grows mostly underwater but can form dense mats along the surface. Leaves grow in whorls around the stem making a cylindrical shape and the stems are very leafy compared to the native elodea, common waterweed (Elodea canadensis). There are usually 4 to 8 leaves in a whorl and the leaf edges appear smooth to the naked eye (native elodea has 3 leaves in a whorl). Small white flowers appear from spring to late summer. They have three petals and float on or rise above the water's surface on thread-like stems.
Legal status in King County, Washington
Public and private landowners are required to control infestations of Brazilian elodea that occur on their property in King County, Washington except in lakes Dolloff, Fenwick, Union, Washington, and Sammamish, and the Sammamish River. Brazilian elodea is a Class B Noxious Weed in Washington, first listed in 1993. It is designated by the Washington State Noxious Weed Control Board for required control in King County except in areas as described above. It is on the list of Regulated Class B Noxious Weeds in King County.
This species is also on the Washington quarantine list (known as the prohibited plants list) and it is prohibited to transport, buy, sell, offer for sale, or to distribute plants or plant parts of this species, into or within the state of Washington. It is further prohibited to intentionally transplant wild plants and/or plant parts of this species within the state of Washington.
For more information on noxious weed regulations and definitions, see Noxious Weed Lists and Laws.
Additional information on Brazilian elodea
- King County Best Management Practices for Brazilian Elodea
- Technical Information Bulletin from the WA State Department of Ecology
- Washington State Noxious Weed Control Board (external link)
What to do if you find this plant in King County, Washington
Please notify us if you see Brazilian elodea growing in King County. Our program staff can provide the property owner or appropriate public agency with site-specific advice on how best to remove it. We map all known locations of regulated noxious weeds such as Brazilian elodea in order to help us and others locate new infestations in time to control them.
Brazilian elodea photos
Report brazilian elodea in King County, Washington
- Please notify us through our online infestation form
Locate brazilian elodea in King County, Washington
- Use our interactive noxious weed map and search for brazilian elodea