Quick Facts

Scientific nameHydrilla verticillata
OriginSoutheast Asia
IntroductionEarly 1950s, aquarium trade
Aquatic communitySubmersed, surface mats
HabitatInches to 35 feet deep
Management effortMaintenance control
2015 public waters / plant acres:

185 / 21,837

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

FWC Hydrilla Management Position (PDF)
FWC Hydrilla Management Position Background Information (PDF)

Hydrilla verticillata
Hydrilla verticillata
Jeff Schardt (FWC) holding hydrilla
Jeff Schardt (FWC) holding hydrilla

Management Options

BiologicalSterile grass carp stocked in about 100 public lakes; 4 host-specific insect species released with few successes; FWC is not currently funding overseas exploration for additional host-specific insects
ChemicalLarge-scale: potassium endothall, bispyribac, flumioxazin, fluridone, penoxsulam; topramezone - small-scale: copper, diquat - research is focusing on combinations of herbicides, especially contact type herbicides with systemics
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 December 2014