Quick Facts

Scientific nameHydrilla verticillata
OriginSoutheast Asia
IntroductionEarly 1950s, aquarium trade
Aquatic communitySubmersed, surface mats
HabitatInches to 35 feet deep
Management effortMaintenance control
2013 public waters / plant acres:

187 / 28,610

Environmental and Economic Concerns

  • Stems can elongate as much as 6-8 inches per day in Florida's peak growing season
  • Can cover entire water body surface 1-2 years after introduction
  • 80% of plant mass is in the upper two feet of water column
    • blocks sunlight and shades out native plants
    • blocks air exchange and consumes oxygen, leading to fish kills
    • blocks access, navigation, and recreation
    • breaks loose and jams against bridges and dams
  • Reduces recreation-based incomes and property values
  • Doubles sedimentation rate from senescing leaves and stems
  • Disperses by fragments, buds, and runners (does not produce seeds)
  • Resists long-term control via underground propagules (tubers)
    • millions produced per acre
    • no effective tuber control method
    • viable tubers lie dormant for as long as seven years
Hydrilla verticillata
Hydrilla verticillata
Jeff Schardt (FWC) holding hydrilla
Jeff Schardt (FWC) holding hydrilla

Management Options

BiologicalSterile grass carp; host-specific insects (few insect successes to date); testing a pathogen in conjunction with herbicides; overseas exploration continues for additional host-specific insects
ChemicalLarge-scale: endothall, bispyribac, flumioxazin, fluridone, imazamox, penoxsulam; topramezone - small-scale: copper, diquat; and combinations of herbicides
MechanicalHarvest from spring runs and boat trails in deep water, harvest / shred mats lodged against structures (bridges, dams)
PhysicalHand pull / diver dredge new infestations, or in fast-flowing water

Florida Fish & Wildlife Conservation Commission, Status of the Aquatic Plant Maintenance Program in Florida Public Waters, Annual Report – Fiscal Year 2009-2010.

Last updated: 30 June 2014