Invasive hydrilla. (hiindy22 / iStock)

The Illinois Department of Natural Resources has confirmed that hydrilla (Hydrilla verticillata) — “considered one of the world’s worst aquatic weeds” — has been discovered in DuPage County.

This marks only the second known report in Illinois, IDNR officials said.

According to Naperville-based The Conservation Foundation, IDNR was notified of the invasive species by a homeowner’s association on Ginger Creek in Oak Brook. 

Hydrilla, which is banned in Illinois, may have been unintentionally released from a homeowner’s aquarium or a water garden, officials said, which is how the plant was introduced into U.S. waterways in the first place.

The plant can grow up to an inch per day and forms dense mats of vegetation that “choke waterways, block sunlight and drastically alter the water chemistry,” according to the North American Invasive Species Management Association.

Along with crowding out and displacing native plant species, hydrilla reduces oxygen levels in water, killing off fish and other aquatic species. Hydrilla’s presence can also affect human health by creating stagnant waterbodies that promote mosquito breeding.

A team from IDNR and The Conservation Foundation recently scoured sections of Salt Creek near the waterway’s mainstem, looking for signs that hydrilla may have spread further into the watershed. Salt Creek feeds into the Des Plaines River, which in turn flows into the Mississippi.

The plant can be difficult to detect, as it can spread via underground tubers, with no visible surface growth.

IDNR is currently developing a containment and eradication strategy, the agency said. 

To limit the spread of hydrilla and other aquatic invasive species, IDNR advised people to:

— Remove all plants, animals and mud from any equipment that is used in waterbodies.

— Drain all water from boats and gear.

— Dry everything thoroughly with a towel or heat.

—Do not dispose of plants or animals from aquariums or water gardens in local waterbodies.

Anyone who suspects they've seen hydrilla in a waterbody should notify the IDNR Aquatic Nuisance Species Program at [email protected].

Here are tips on how to identify the plant:

Contact Patty Wetli: @pattywetli | (773) 509-5623 |  [email protected]