Weeds Watch Out:  Hydrilla


Hydrilla (Hydrilla verticillata )






Hydrilla. Robert Johnson, Cornell University.  Ruthanna Hawkins, Cayuga Lake Watershed Network.  Used with permission.
Hydrilla. Robert Johnson, Cornell University. Ruthanna Hawkins, Cayuga Lake Watershed Network. Used with permission.
Hydrilla Drawing, University of Florida, Center for Aquatic and Invasive Plants Line Drawing DVD Master.  Used with permission.
Hydrilla Drawing, University of Florida, Center for Aquatic and Invasive Plants Line Drawing DVD Master. Used with permission.
  • Native to India/Korea

  • Reported in North America in late 1800s

  • Plant Characteristics

    • Submersed, rooted perennial plant that forms a dense mats from the bottom to the top of the water column (2 inches to 20 feet)

    • Also found as detached floating mats

    • Can grow in deep water up to 20 feet

    • Leaves are lance-shaped in whorls of 4 to 8

    • Leaves are small, sharply toothed with red mid-rib and distinct toothed edges

    • Leaves feel scratchy from spines on the underside of the leaf

    • When pulled from the sediment, tubers might be seen

    • Grows in various depths, nutrient levels and temperatures

    • Commonly spread by plant fragments attached to boating equipment

    • Reproduces by regrowth of stem fragments and by axillary buds (turions)

    • Inhibits swimming, boating, and water recreation

    • Found in springs, lakes, marshes, ditches and rivers

    • Not in the Oswego River Basin at this time
Hydrilla Location Map, USGS, Nonindigenous Aquatic Species
Hydrilla Location Map, USGS, Nonindigenous Aquatic Species

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Page updated on August 12, 2005.