Skip to main content

Eurasian Watermilfoil

photo of a patch of Eurasian Watermilfoil
Robert L. Johnson, Cornell University, Bugwood.org

Category
Invasive

Description

Eurasian Watermilfoil is native to Europe, Asia, and northern Africa. Not much is known about when or how it was introduced, but it was likely between the 1880s and 1940s and possibly through the aquarium trade or transported on watercraft and equipment.  

Was first observed in Oklahoma in 1959 in Spavinaw Lake, and has since been found in Comanche City, Prague City, Pauls Valley City, Sportsman, Jap Beaver, Lawtonka, Sooner, Quanah Parker, Carl Etling, Humpherys, Fuqua, Robert S. Kerr, Stanley Draper, Fort Cobb, Elmer Thomas, Chandler, Purcell City, Clear Creek, Shawnee Dead Warrior, Longmire, Cleveland City, Dahlgren, Elk City, and Rush Lake.  

Impacts 

The major impact that Eurasian watermilfoil causes is that it can crowd out native plant species, along with hybridizing with some native plants. It also creates a canopy-like structure toward the water surface that can cause boating issues. Eurasian watermilfoil is easily spread by fragments that are carried by boat, trailer, and other gear.  

Identification Keys 

  • Leaves are feather-like with four arranged in a whorl pattern around the steam, with 14 or more leaflets on each leaf 
  • Tips of the plant is sometimes red or pink in color 
  • Pink terminal spike (up to four inches long) produces tiny yellow flowers 
  • Grows between 1-4 meters, but can extend up to 10 meters in height

How To Observe

If you think you have discovered any invasive species contact us at (918) 200-4815 or report online.

Report Online ANS Regulations

Explore more Oklahoma Invasive

photo of invasive Brittle Naiad infestation at Robert S Kerr
Photo by: okinvasives.org
photo of a patch of Eurasian Watermilfoil
Photo by: Robert L. Johnson, Cornell University, Bugwood.org
Photo of a Harris Mud Crab
Photo by: Robert Aguilar, SERC