parrotfeather watermilfoil

Haloragales > Haloragaceae > Myriophyllum aquaticum (Vell.) Verdc.
Synonym(s): water-feather, Brazilian water-milfoil, parrotfeather

Parrotfeather watermilfoil is an herbaceous, rooted, submerged/emergent plant that invades aquatic habitats throughout much of the United States. Stems are stout and blue-green in color. Leaves are abundant, whorled, pinnately compound, and finely dissected. Submersed leaves are 0.6-1.4 in. (1.5-3.5 cm) long and have 20 to 30 divisions per leaf. Emergent leaves are 0.8-2 in. (2-5 cm) long, less divided and greener than the submersed leaves. As only female plants occur in North America, reproduction occurs vegetatively. Inconspicuous flowers are formed in the axils of the emergent leaves in the spring (sometimes fall). Parrotfeather watermilfoil is found in lakes, ponds, and slow moving streams where it can form dense mats of vegetation. These mats can clog waterways, impede boating traffic, disrupt the growth of native vegetation and provide a breeding ground for mosquitoes. Parrotfeather watermilfoil is native to South America and was first introduced into the United States in the Washington DC area around 1890 as an aquarium and aquatic garden plant.

Identification, Biology, Control and Management Resources

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Infestation; Control with 2,4-D and wetting agent
Utah State University Archive, Utah State University,
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Alison Fox, University of Florida,
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Alison Fox, University of Florida,
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Plant(s); Close-up with pennywort in center
Alison Fox, University of Florida,
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Foliage; Emergent stems
Leslie J. Mehrhoff, University of Connecticut,

Nancy Loewenstein, Auburn University,
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Invasive Reference(s):

Check for most current lists.
  • Alabama - Noxious Weed Law
  • Alabama - IPC List
  • California - Invasive Plant Inventory
  • Connecticut - Noxious Weed Law
  • Georgia - EPPC list
  • Maine - Noxious Weed Law
  • Massachusetts - Noxious Weed Law
  • Tennessee - EPPC List
  • Texas - Invasive Plant List
  • Vermont - Noxious Weed Law
  • Virginia - Invasive Alien Plant Species
  • Washington - Noxious Weed Law
  • Mid-Atlantic - EPPC List
  • Invasive Plants of the Upper Midwest
  • Invasive Plant Atlas of New England

External Links

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USDA Forest Service Bugwood University of Georgia