A recent assignment took me to Seven Generations Charter School to learn about, of all things, invasive plant species.

The young interviewees were well-versed and enthusiastic about the topic of the Japanese knotweed plants causing trouble along a small stream bed on their campus on Minor Street, Emmaus.

The students spoke of towering shrubs near a playground and across the street near the middle school building and how, when investigating the plants, some students appeared to get lost in thickets of foliage.

Among strategies to remove the knotweed, students considered using insects known to eat the plant to mow down the shrubs, so to speak, according to Lyla Mahmoud, a fifth grader at the school. But that would create another problem: Getting rid of the insects.

Such is the slippery slope of invasive plant species.

The Nature Conservancy points out whether intentionally or unintentionally introduced into an area, invasive species, plant and animal, often lack natural competitors or predators in the new area where they are placed thereby earning the distinction of description as “invasive.”

Japanese knotweed, I learned, arrived in the United States in the mid-to-late 19th century, imported to be used for landscaping and erosion control. According to a fact sheet from Penn State, Japanese knotweed is native to Japan, China, parts of Korea and Taiwan. The plant was sold through nursery catalogs. Leaving its natural predators halfway around the world, the plant quickly spread, its complex root system stretching deep into the ground and making it difficult to pull up the plant, as my fifth grade mentors found out by experience.

Crews from the Borough of Emmaus recently used heavy equipment to remove shrubs of the invasive plant.

“We went into the water,” Joanelys Cortes, recalled about the students’ experience in assessing the knotweed problem. Students found “tiny trout.” Cortes said.

The students at Seven Generations Charter School identified the Japanese knotweed problem themselves, Barbara Lindtner noted. Lindtner teaches third grade at the charter school. Working with Lindtner and with several other groups, including the Lehigh County Conservation District, Borough of Emmaus and Wildlands Conservancy, the students applied for a grant from the Department of Environmental Protection to remove the invasive knotweed and replant with native plants.

That was two years ago when the students were in third grade.

Earlier this month, the students, now fifth graders and Lindtner celebrated the $32,000 grant award.

A representative from Penn State Cooperative Extension acknowledged the efforts by the students. Landscapers and home gardeners who liked the white flowers knotweed produces likely never thought the plants would pose a problem.

In the age of global trade and relative ease of travel, however, such concerns can be paramount,

For instance, according to the Nature Conservancy, a tiny mussel released with ballast water by a tanker ship into the Great Lakes now threatens “to smother 140 native mussel species, and waterfront industries, like dams and power plants, must pay billions in ongoing repairs to clogged pipes while passing the cost to consumers.”

And do not mention the cane toad.

According to the Pennsylvania Department of Conservation and Natural Resources, invasive species “can cause harm to the environment, to the economy and to human health.”

Furthermore, according to a Cornell University study cited by PDCNR, invasive species cost $130 billion a year. That is last week’s $1.6 billion Powerball jackpot several dozen times over.

Plus, invasive species may take a larger ecological toll threatening some native species populations with collapse.

The road back from removal of an invasive species can be an arduous and intentional one. Restoration is deliberate work. And vigilance is required to guard against return of an invader or the introduction of new less than friendly plants.

The PDCNR recommends selecting plants native to an area when replanting or when planting for the first time. A brochure of plants considered invasive to Pennsylvania is available through the PDCNR website along with a list of steps home gardeners and others can take to steer clear of invasive plant species.

Thank you to my fifth grade mentors for sharing their knowledge.

April Peterson

editorial assistant

East Penn Press

Salisbury Press