Invasive plants have washed into Bayou St. John, hugging the banks of the popular New Orleans waterway and raising concerns that they could endanger its environmental health.

The mats of plants are more than just an eyesore and an obstacle for those who use the bayou. Left unchecked, they could cause serious problems.

“It’s something that if we don’t take care of it immediately, it could become bad and also hurt the marine life as well, the native plants and animals,” said Sarah Howard, of the Kayak-iti-Yat tour company.

Howard and others are trying to organize an effort to clear out the hyacinths and salvinia that have invaded the bayou, likely after being swept in from Lake Pontchartrain when the floodgate between the two bodies of water was opened about a week ago.

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Salvinia, a type of invasive floating fern, fills a corner of Bayou St. John near City Park in New Orleans, La., Friday, Feb. 1, 2019.

Hyacinths and salvinia both grow rapidly. And because nothing in the local environment eats them, there’s nothing to keep them from spreading across the entire waterway unless they’re hauled out.

In a worst-case scenario, the plants could cover the entire bayou, choking the plants and animals that live there, Howard said.

Other local waterways in City Park and parts of Bayou Bienvenue have had to deal with such invasions, she said.

New Orleans city officials did not respond to questions Friday.

Howard said that those concerned about the plants have reached out to the Lake Pontchartrain Basin Foundation for help and are working to organize volunteers who would go out weekly to clear out the unwelcome invaders. Potential plans include gathering the plants by hand or setting up nets to catch them as they float down the bayou.

“It’s going to take a lot of manpower, scooping it out, and then we have to find a place to put it,” she said.

A similar effort was undertaken in 2017 and succeeded in clearing out invasive plant life, City Park then allowed volunteers to dump the plants in the park's compost area.

In the meantime, Howard encouraged anyone near Bayou St. John to pitch in.

“If you see these plants, whether it’s a lot or a few, just try to get them out. It just takes diligence,” she said.


Follow Jeff Adelson on Twitter, @jadelson.​