A stretch of tangled, mostly invasive plants that has taken over the Merrimack River riverbank by Fort Eddy Plaza in Concord will be mowed down this winter as the first step of possible eradication, and with any luck, the owners of nearby land will join in.

“I’m hoping everyone from Einstein’s up to NHTI can sign on,” said Tom Schurman, project manager with Outside Unlimited, the landscape management firm that has been hired to do the work by the owners of the plaza off Exit 14 in Concord. He was referring to a stretch of riverbank owned by the franchised bagel restaurant to the south and the community college to the north.

Schurman said they will be working on about two acres of land on the western bank of the Merrimack River when conditions are right – meaning the ground is frozen so that it isn’t too muddy for equipment and the river level is lower than right now. The goal, he says, is to control a vast tangle of invasive plants such as barberry, bittersweet, Japanese knotweed and Asian silk grass.

“It has just completely taken over. It makes a thick canopy, really restricts native species from taking root underneath,” he said. “These invasive climates are like jungles. They trap an enormous amount of garbage; native forests are a little more open.”

There’s even a human health aspect to fighting these invasives.

“Barberry creates a level of humidity underneath them, it’s so dense and thick … they actually increase tick reproduction. … The ticks love it, the perfect climate for them to over-winter,” he said.

Under the proposal the invasive plants will be cut down this winter, and then will be sprayed with herbicide in the fall, when such spraying is most effective because plants are taking the maximum amount of material down into their roots as preparation for winter. Most invasive plants cannot be controlled by merely cutting them back repeatedly; their ability to quickly regrow is one of the reasons that they can overwhelm native species. The project could cost up to $50,000.

The work could affect some homeless people, who often set up along this stretch of the Merrimack River.

Invasive plants, insects, birds and animals are a problem all over the world. They are non-native species that for various reasons, especially a lack of predators in their new home, spread so quickly that they drive out native species and upset established ecosystems.

Schurman said getting permits to spray along the riverbank took months of meeting with state environmental and wildlife officials, who he said were very helpful.

“The permitting process to do any kind of work on the water is an absolute headache,” he said. “Getting the permit is hard, and then being watched like a hawk after that – not a lot of loggers and landscapers will even try.”

Schurman said he has found in New Hampshire, at least, it’s harder to tackle invasive plants on land than invasive in water, such as Eurasian milfoil or water chestnut. 

“Not a lot of people will pay attention to these land-based invasives,” he said. “Almost all grants deal with aquatic invasives.”

The affected stretch of riverbank includes parcels owned by a number of organizations, including the city, the state and private companies. Increasing the area covered by the project would not only help control the plants, which easily spread, but can also spread out the cost.

Schurman said that he wants to make sure that Concord doesn’t end up like parts of Massachusetts where Outside Unlimited often works.

“It’s overrun down there. It almost looks like there’s no native forest left,” he said. 

(David Brooks can be reached at 369-3313 or dbrooks@cmonitor.com or on Twitter @GraniteGeek.)