• Eurasian Watermilfoil Plant 215x150

Category A Weed

Watermilfoil family (Halorgaceae)

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Eurasian watermilfoil (Myriophyllum spicatum)


    • Aquatic weed up to 12 ft. long, submersed, branched near water surface, growing points often reddish; breaks into fragments easily


      • Whorled with 4 leaves per node; leaves are green to brown, less than 1.25 in. long and pinnately-divided with more than 14 pairs of narrow, opposite lobes (less than 0.4 in. long)


        • Pinkish and small, each with a small, bract-like leaf

        • Occur in clusters on small, pencil-like stalks that emerge from water (1-3 in. long); stem often bends to become parallel with the water surface after flowering


          • Creeping rhizomes


            • Most common in still or slow-moving water but can sometimes be found in fast-moving rivers, streams and irrigation ditches; known to occur in Churchill, Douglas Washoe and White Pine counties

            • Perennial; reproduces by rhizomes, stem fragments and seed


              • Mechanical removal can be effective but must be done repeatedly; escaped stem fragments can form new plants; draining then allowing an empty water-body to freeze can be effective

              • Aquatic herbicides such as 2,4-D, diquat, endothall, triclopyr, fluridone and copper complexes are effective