Watch Out for Hydrilla in Lake George

closeup view of a hydrilla plant

Hydrilla is NOT currently known to be in Lake George.  Early detection of this potential invasive species in shoreline or dock areas is key to its management. Hydrilla is part of our Lake George Invaders Watch citizen science program.  If you think you have found Hydrilla, please contact us.

The Threat

Hydrilla (Hydrillaverticillata) is a submerged perennial that is currently present in 15 New York State waterbodies. Due to its ability to spread rapidly and completely clog waterways, hydrilla poses significant threats to the aquatic ecosystem and recreational resources. Hydrilla can reduce plant diversity by outcompeting native aquatic plants. Dense infestations of hydrilla can affect water quality and impede water flow, which can result in flooding and damage to shorelines and structures. Thick mats of hydrilla make swimming and other recreational activities difficult, if not impossible.

dense mat of hydrilla on lake surface hydrilla, a potential invasive species to Lake George


This plant is tolerant of a wide range of environmental conditions and can be found in lakes, ponds, reservoirs, rivers, canals, and drainage ditches. It has low light requirements and thrives in both high and low-nutrient waters.

Identifying Hydrilla

closeup views comparing hydrilla to waterweed and other common plants
Hydrilla compared with Waterweed and Brazilian elodea

Hydrilla looks similar to American waterweed (Elodea canadensis), which is a native aquatic plant in Lake George. Hydrilla is a potential invasive species that has visibly serrated leaves that grow in whorls of 3-8. Undersides may have one spine or more, and the midrib of each leaf is often reddish. Hydrilla spreads by seeds, tubers, plant fragments, and turions (overwintering buds). Use the photos here and this checklist for hydrilla identification to help you identify this plant.

closeup of base of hydrilla plant
Hydrilla has small potato-shaped tubers with white rhizomes
closeup of hydrilla leaves showing serration
Hydrilla has serrated leaves
closeup view of hydrilla stem showing leave pattern
Hydrilla has lance-shaped leaves in whorls of 3-8


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Lake George Association

Lake George Association