Weed of the Week

1-28-08

Eurasian Milfoil, Myriophyllum spicatum

             

 Photo credits: Native watermilfoil on right, Eurasian watermilfoil on the left, photo courtesy of Washington Dept. of Ecology.  Alison Fox, University of Florida, Bugwood.org

 Characteristics:

Family: Haloragaceae

Origin: Europe and Asia

Description:

• Non-native, aquatic, perennial species

Stems:

• Stems pinkish on the end and double in size below the inflorescence

Flowers:

• Small pinkish flowers that occur on portions of the plant above the water

• Become submerged when pollinated

Leaves:

• Leaves occur in whorls of 4-5 with 5-24 leaflets per leaf

• Easy to confuse with Native watermilfoil which has less leaflets and is not as intrusive.

Fruit:

• Does produce fruit but seeds rarely produce seedlings

Additional Information:

Eurasian watermilfoil is a Class B noxious weed in Colorado.  It is problematic in that it forms dense mats that suffocate out other native plants.  Also the massive matting creates poor wildlife and fish habitat.  The organic overload of the mats causes oxygen depletion as the plant deteriorates and changes the Ph of the water.  Eurasian watermilfoil also creates problems for boaters and fisherman and is easily spread through movement of recreational equipment from an infested body of water to another.  Boats should be cleaned after leaving infested waters or entering bodies of water that do not have Eurasian watermilfoil.  Currently in Broomfield County there are not infestations of Eurasian watermilfoil

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