SLELO PRISM

Hydrilla (Hydrilla Verticila) is a submerged aquatic plant that roots in the bed of a waterbody. It is native to Africa, Australia, and parts of Asia. It is considered the most problematic aquatic plant in the US. there are two varieties of hydrilla in the US; one produces only female flowers making it monoecious, while the other is dioecious and produces both male and female flowers. The plants in New York are dioecious and produce both female and male flowers. It is believed that hydrilla was introduced in the US via the aquarium trade. Hydrilla is a federally listed noxious weed, listed as a Class A weed on Washington’s Noxious Weed List, and is on the Washington State Department of Agriculture’s Quarantine list

Impacts

Hydrilla invades deep, dark waters where most native plants can’t grow; it is more efficient at taking up nutrients than native species and has the ability to produce turions and tubers which can easily generate new plant. These characteristics give hydrilla a competitive edge against native aquatic vegetation.  Furthermore, hydrilla populations block out sunlight and suppress native vegetation. Major hydrilla colonies can alter the physical and chemical characteristics of lakes, deter recreational activities, and reduce lakeshore property values. 

Habitat/Distribution

Hydrilla is found in fresh waterbodies and is well established throughout southern portions of the US.