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Eurasian watermilfoil

Quick facts

Eurasian watermilfoil is a prohibited invasive species. It is illegal to possess, import, purchase, transport, or introduce these species (including hybrids or cultivars) except under a permit or statutory exemption. Transport directly to the Minnesota Department of Natural Resources in a sealed container for identification or reporting purposes is permitted.

  • Eurasian watermilfoil can form dense mats at the water's surface, reducing light penetration and inhibiting water recreation. 
  • It can displace native plants and form dense monocultures that may not provide suitable shelter, food or nesting habitats for native animals. 

Eurasian watermilfoil should be reported. See the Minnesota Department of Natural Resources recommendations for reporting invasive species.

Eurasian watermilfoil in the water

How to identify Eurasian watermilfoil

  • Eurasian watermilfoil (Myriophyllum spicatum) is a submerged aquatic plant that can form dense branching at the water's surface. 
  • Typically grows in waters up to 15 feet deep.

Stem

  • Range in color from a reddish brown to green to whitish pink. 
  • Will often branch.

Leaves

  • Soft, feather-like leaves that are noticeably divided with 12-20 leaflet pairs along a central axis. 
  • Arranged in whorls of four around the stem. 
  • Leaves are typically limp when removed from water. 

Flowers

  • Inconspicuous flowers form on spikes that rise two to four inches above the water’s surface.
  • Typically pink in color. 

Roots

  • Can produce roots at each node along the stem. 
  • Reproduces primarily by autofragmentation, when roots that develop at the nodes break off and grow into new plants.
curvy stem of Eurasian watermilfoil on white background
Eurasian watermilfoil
top view of Eurasian watermilfoil to show four branches.
Eurasian watermilfoil

 

Angela Gupta, Extension educator; Amy Rager, Extension educator; Megan M. Weber, Extension educator

Reviewed in 2019

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