Hydrilla (Hydrilla verticillata)

Category A Weed

Waterweed family (Hydrocharitaceae)

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  • Aquatic weed up to 25 ft. long, submersed, slender and branched near water surface


    • Strap-like (linear) to lance-shaped, 0.25-0.75 in. long and less than 0.2 in. wide; NO leaf stems (petioles); arranged in whorls of 4-8 around stem; edges (margins) are toothed; midvein on leaf underside often has one or more sharp teeth


      • Small, white, attached to threadlike stalks up to 4 in. long and float on water surface


        • Unbranched, slender and white; yellowish, potato-like tubers (0.25-0.5 in. diameter) form at root tips


          • Often found in still or slow-moving water; not known to occur in Nevada

          • Perennial; reproduces by stem fragments and tubers; occasionally produces turions at leaf axils; turions are mostly cylindrical, dark green reproductive structures up to 0.5 in. long

          • Listed on the Federal Noxious Weed List


            • Mechanical removal can be effective but must be done repeatedly; escaped stem fragments can form new plants

            • Grass carp can be an effective biological control

            • Aquatic herbicides such as diquat, endothall, fluridone and copper complexes are effective


              Hydrilla Plant
              Mature Plant
              Hydrilla Leaves
              Hydrilla Infestation
              Hydrilla Tuber
                Nevada Noxious Weed Field Guide
              Nevada Noxious Weed Guide