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Texas by Nature

Invasive Hydrilla Threatens Texas Rivers, Lakes and Streams

Landowners, boaters urged to be vigilant to halt spread of "world's worst weed"

By Jay Harrod

Hydrilla, known as the “world’s worst weed” came to Texas, as it did to much of North America, through the aquarium trade. While the lush stems of this aquatic plant offer terrific cover for goldfish, they also grow in thick mats that quickly take over entire lakes, crowd out native plants and damage populations of popular sportfish species.

In little more than 50 years, this invasive has established itself in nearly half of U.S. states. A bane to boaters and fishermen, hydrilla is also known for clogging up industrial pipes at factories and water treatment plants, costing the nation millions every year.

“Texans should be on the lookout for this very aggressive plant,” said Jim Bergan, director of science and stewardship for The Nature Conservancy of Texas. "I first encountered hydrilla when I worked for the game commission in Florida, where we spent millions of dollars controlling its spread. Texas needs similar funding just to make a dent in the present infestation across the state."

Today, hydrilla is listed as a Federal Noxious Weed and is illegal to sell at pet stores. Unfortunately, some sales continue through the Internet. Once it is established in non-native waters, removing the weed is extremely difficult, often requiring a combination of mechanical response, herbicides and introduced predators.

To help combat the spread of hydrilla, Texans are urged to take these precautions:

•    Avoid boating through hydrilla mats. This will minimize fragmentation and the spreading of plants.

•    Remove all plant fragments from the boat, propeller, and trailer before and after boating.

•    Always dispose of plant fragments on the shore.

•    Rinse any mud and debris from equipment and gear before leaving a launch area.

•   Drain any water from the boat before leaving.

•    Do not dump aquarium or water garden plants outside. Do not flush them down the toilet. Seal them in a plastic bag and throw in the trash.

•    Look for Texas native plants to add in aquariums and water gardens instead of exotic and invasive species such as hydrilla.

For more information on invasive species control or other Conservancy work, visit nature.org/texas.

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