Hydrilla, an invasive aquatic plant, has been detected in DuPage County. This marks the first known occurrence in the county and the second report in Illinois. Hydrilla is considered one of the world's most problematic aquatic weeds due to its rapid growth rate and ability to form dense mats that negatively affect boating, fishing, swimming, native wildlife, and property values. Efforts to control and eradicate hydrilla can be costly and prolonged.
The Illinois Department of Natural Resources (IDNR), alongside other state and local agencies, is monitoring the spread of hydrilla in waterways and evaluating containment and eradication strategies. The public should note that hydrilla resembles the native Elodea species but can be distinguished by its whorls around the stem with more than three leaves often featuring visibly toothed edges.
The introduction of hydrilla into DuPage County may have occurred through accidental release from aquariums or water gardens. Despite being classified as a federal noxious weed—illegal to buy, sell, or transport—and banned in Illinois, it remains prevalent in aquarium and water garden trades.
To help prevent the spread of hydrilla and other aquatic invasive species, individuals are encouraged to remove all plants, animals, and mud from equipment used in water bodies; drain all water from boats and gear; dry everything thoroughly; and avoid disposing of plants or animals from aquariums or water gardens into local water bodies.
Suspected sightings of hydrilla should be reported to the IDNR Aquatic Nuisance Species Program at dnr.ans@illinois.gov. For further information on hydrilla, refer to the Great Lakes Hydrilla Collaborative.
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