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10/27/2022 12:00 AM

Slow Down: It’s Time to Rethink Invasive Plants

Let’s Go After the Bullies

As someone who works in the land care business, I sometimes begin to feel as though I’m caught in an endless game of whack-a-mole. From spotted lantern flies to jumping worms, from knotweed to tree-of-heaven, landscape invasive species grabbed a lot of headlines in the past year and made my life in the landscape more challenging. Sometimes I think, who needs Halloween or a scary movie?

I’d like to believe there are more systematic, less fatiguing ways to think about the problem of invasive plants. The theme of the 2022 Connecticut Invasive Plant Working Group (CIPWG) biannual symposium suggests there are.

Titled “Strategies for Managing Invasive Plants: Assess, Remove, Replace, and Restore,” the symposium will be webcast on Thursday, Nov. 3. Don’t worry if you can’t attend that day. Just be sure to register by Tuesday, Nov. 1 and you can access the recordings and handouts until spring 2023. Registration information is at the end of this story.

CIPWG’s headline speaker this year, Bernd Blossey, has made a career investigating the phenomenon of invasive ecology. He is a leading proponent of the idea that we should step back and look at the bigger picture before reacting to invasive species. I first heard Blossey speak about ten years ago and he opened my eyes to the possibility that garlic mustard—a listed invasive plant—may be self-limiting and not worthy of as much attention as it sometimes gets. In addition, he offered that many invasive plants that may be in the same category.

Blossey runs Cornell University’s program in Ecology and Management of Invasive Plants, and his research has produced some controversial perspectives on the problem.

“Plants are always visible and can’t run away, and land managers feel the need to ‘do something’. But the plants are not always the agents of change,” he said in a recent interview. “We blame introduced plants such as Japanese stiltgrass and garlic mustard for the ill effects we see in a landscape. But we must figure out whether the plants are the real drivers.”

He went on to describe a scenario all too familiar to me.

“Land managers have a constant drive to improve conditions for the native species they care about,” he says. “But if we engage in management without research, we may not change the drivers that lead to invasiveness. The outcome can be bad.” He adds that he and his students hear many land managers say they don’t have the time or technology to monitor the results of their invasive plant removal programs. “They manage plants in hopes that the outcome will be better,” he says. But he likens this approach to outspending your credit card limit and hoping the someone will pay the bill.

Blossey continues, “We know the vast majority of non-native, imported plants do not become invasive. The big question is this: Which ones are self-limiting, and which are the bullies?”

Blossey develops and implements biological weed control programs; among his target plants are two he calls “bullies,” Japanese knotweed and phragmites. “These do not seem to be self-limiting,” he says.

His team increasingly focuses on impacts of multiple landscape “stressors,” which he suggests are often earthworms, slugs, and deer. He is deeply involved in different approaches to deer management at Cornell.

Blossey’s talk is titled “Invasive Plant Management: What We Know, What We Do Not Know, and What We Must Know.”

The day-long CIPWG symposium program offers twenty-one additional speakers and topics, many designed to benefit homeowners and municipalities, in addition to those managing conservation lands.

Bryan Connolly, assistant professor at Eastern Connecticut State University, will describe online tools and apps for identifying and reporting invasive plants. Breakout sessions include managing mile-a-minute vine in the backyard and managing other invasive plants at home. There are sessions on landscape assessment and restoration, including propagating native plants from seed, sourcing native seeds, and designing with native plants.

Other sessions include “Targeting Tree-of-Heaven,” “Disposal of Invasive Plants,” “Roles and Expectations of Municipalities and their Residents.” There is a session on invasive removal in wetland areas, and one describing when to hire a licensed professional pesticide applicator.

There will be reports on a ten-year program for biological control of mile-a-minute weed, hydrilla management, and managing water chestnut. Diane Jorsey, Supervisor of the Pesticide Management Program at CT Department of Energy and Environmental Protection will speak on requirements for pesticide applications on conservation lands.

If you are ready to step back and look at the bigger picture of invasive plants—and wholistic approaches to reclaiming land--register for the webcast CIPWG symposium by Nov. 1.

WHAT: Virtual Event: Strategies for Managing Invasive Plants: Assess, Remove, Replace, and Restore

WHEN: November 3, 2022; 8:30 a.m. to 4 p.m., plus unlimited access to all webcast presentations and handouts through spring 2023.

WHO: Connecticut Invasive Plant Working Group (CIPWG)

WHERE: Webcast on your computer on Nov. 3 and after

NOTES: CEUs for professional certifications and Pesticide Recertification Credits available.

COST and registration: $65 by November 1. Registration provides access to the webcasts and handouts through spring 2023. $25 Students. MORE INFO:

Bernd Blossey, left, is a professor at Cornell University, directing the Ecology and Management of Invasive Plants Program in the Department of Natural Resources. He will deliver the keynote address at the Connecticut Invasive Plant Working Group Symposium, which will be webcast on Nov. 3. Photo: Courtesy of Bernd Blossey
Invasive plant disposal is one of many topics in the CIPWG Symposium, to be webcast Nov. 3. Photo courtesy of Kathy Connolly
Japanese knotweed is one of a small number of invasive plants that are landscape “bullies,” according to Bernd Blossey. Unlike some nonnative plants, “These do not seem to be self-limiting,” he says. Photo courtesy of Barbara Harms
Native Christmas ferns thrive where invasive Japanese barberry was eliminated. Photo courtesy of Kathy Connolly

Kathy Connolly writes and speaks on land care, landscape ecology, and horticulture from Old Saybrook. She will speak at the CIPWG symposium on “Managing Invasive Plants at Home: Details that Make a Difference.” Her website is