Asiatic bittersweet grows just about everywhere around Lewiston-Auburn: It can be found climbing up trees, utility poles and even rain gutters.
Asiatic bittersweet vines are commonly seen growing along the road in large clumps. Submitted photo
Originally planted in the U.S. as an ornamental vine in the 1800s, Asiatic bittersweet is now widespread in the northeast, choking trees and out-competing native plants. As the climate warms, the leafy woody vine has moved north through Maine.
With the help of environmental studies students at Bates College in Lewiston, the Lewiston-Auburn Community Forest Board is working to create a management plan to help control its spread and train residents to remove the plant.
Asiatic bittersweet tends to grow in large clumps, damaging the trees the vines climb, spreading diseases and providing ideal habitat for ticks to thrive.
“Management plans are generally pretty simple,” said Lewiston’s city arborist, Stephen Murch. “I mean, there’s only so much you can do.”
As groups in Maine learn more about the harmful effects of invasive species, he predicts more communities will look to create management plans for Asiatic bittersweet and other invasive plant species in upcoming years.
Bates seniors Gabrielle Brewer and Linnéa Selendy went with Murch to five neighborhoods in Lewiston and Auburn this fall to map out where Asiatic bittersweet is growing.
“We were finding it, without leaving the street you know, we were pretty much finding it all over the place,” Murch said. “It’s everywhere.”
Asiatic bittersweet berries can range from bright red to yellow. Maine Department of Agriculture, Conservation & Forestry
In just the five neighborhoods they mapped, Brewer and Selendy said about 60% to 70% of the properties had Asiatic bittersweet.
“Bringing that to a larger scale, you can only imagine how much there is all throughout Lewiston and Auburn and other parts of Maine,” Brewer said. “The extent is really shocking.”
But as widespread as it is, few people know how damaging Asiatic bittersweet can be.
“It’s not known commonly that it’s an invasive species,” Selendy said. “We have seen instances, even at Bates College, where people still use it as an ornamental … there is so little general knowledge that’s accessible to people about how dangerous this is.”
Bittersweet is easily spread by wildlife which eat its bright red and yellow berries, eventually depositing the seeds elsewhere. However, it can be difficult to remove.
Asiatic bittersweet vines strangling a tree. Maine Department of Agriculture, Conservation & Forestry
For smaller plants, ripping out the plant with its roots is often enough. But larger, more established plants require a prolonged campaign.
Brewer and Selendy suggest cutting the vines at both chest and ankle height at least six times per year for three to five years. Resprouting can and will occur, making it important to be persistent with cutting, especially during the growing season.
Selendy and Brewer mapped the plant and created educational materials for the Community Forest Board as part of a project-based class for upperclassmen environmental studies majors. But as the class winds down, they’ll likely hand off their work to the next group of Bates students.
A workshop to educate local residents about Asiatic bittersweet and its removal is planned for the spring in Auburn’s Pettingill Park, however the date has not yet been determined.
Comments are not available on this story.
Send questions/comments to the editors.
