Hydrilla (Hydrilla verticillata) is an aquatic plant that is considered to be native to the waters of parts of Asia, Africa, and Australia.
It was first discovered in Kentucky Lake in 1999 along the Tennessee River. It was later found in other water bodies such as Carr Creek, Paintsville, Dewey, and Grayson Lakes. A more recent report placed the aquatic plant in Cave Run Lake also.
The plant is considered to be invasive in Kentucky and other U.S. states. It forms dense mats on the surface of water bodies and fills shallow areas from the top to bottom with vegetation. It chokes other native plants and displaces fish in the area. It is considered to be extremely difficult to eradicate.
It is one of the worst aquatic weeds in the U.S. and infects freshwater lakes, ponds, rivers, and canals.
Hydrilla decreases the biodiversity of water areas and can increase water pH and temperature causing fluctuations in oxygen levels. Hydrilla also clogs pipes and negatively impacts recreational activities like boating and swimming.
Hydrilla is especially problematic because it can grow very fast - 1 inch a day and doubles its size within a few weeks. Even a small 1-inch fragment can result in the creation of a new colony.
The Kentucky Department of Fish and Wildlife Services provides solutions to control and prevent the spread of Hydrilla.
Some ways to stop the spread of Hydrilla include mechanical (i.e. pulling plants by hand), chemical treatments, and biological methods (i.e. removal using other biological species).