Parrotfeather has been popular as an ornamental in ponds and aquariums, but because it rapidly takes over lakes, ponds and ditches, this species is on the Washington quarantine list (known as the prohibited plants list) (external link) 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 laws and lists.
Identification (see below for more photos)Stems are robust, even under water, and roots form along the stem. Flowers are white, tiny and inconspicuous and are found where the above-water leaves attach to the stems. Because all plants in the United States are female, parrotfeather doesn't form seeds but it does spread readily by fragmentation of stems and rhizomes. In King County, parrotfeather emerges in late May and persists into October.
Where it grows
Small populations can be pulled or raked up, being very careful to remove all fragments from the water. Manual control requires persistence over many years.
Aquatic herbicides can be effective if applied correctly, but can only be applied by a licensed pesticide applicator with an aquatic endorsement and will likely require a permit to use in water.
Additional information on parrotfeather
What to do if you find this plant in King County, Washington
Please notify us if you see parrotfeather 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. Also, because parrotfeather is not established in King County, we have an opportunity to stop it from spreading if we act quickly. We map all known locations of regulated noxious weeds such as parrotfeather in order to help us and others locate new infestations in time to control them.
Report parrotfeather in King County, Washington
- Please notify us through our online infestation form
Locate parrotfeather in King County, Washington
- Use our interactive noxious weed map and search for parrotfeather