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A fast-growing vine is one of the newest invasive species identified in Maine

Doug Cygan, an Invasive Species Coordinator for the New Hampshire Department of Agriculture, Markets and Food, pulls a mile-a-minute vine out from a stone wall in Seabrook, New Hampshire.
Caitlin Andrews
/
Maine Public
Doug Cygan, an Invasive Species Coordinator for the New Hampshire Department of Agriculture, Markets and Food, pulls a mile-a-minute vine out from a stone wall in Seabrook, New Hampshire.

The discovery of an invasive vine in Maine has alarmed state officials who keep an eye out for non-native species. It's called the mile-a-minute vine, and despite the name, it doesn't grow 60 miles in one hour. But it can grow up to six inches in a day.

It's just one of many features that have enabled it to become established in the mid-Atlantic and southern New England — and identified in Maine. But there are efforts to keep it at bay.

On this August morning, Mark and Katie Potvin are walking on several parcels of land on a quiet road in Seabrook, New Hampshire.

Along for the hike is New Hampshire invasive species expert Doug Cygan, who has spotted a mile-a-minute plant in the brush next to the road.

Mile-a-minute vine.
Leslie J. Mehroff
/
University of Connecticut via New York State
Mile-a-minute vine.

Cygan grabs the head of the vine and notes its triangular leaves, a thorny stem and bright, blue berries.

"When you know what you're looking for, you know what you're looking for," says Katie Potvin.

Before this sighting, mile-a-minute had been found in only five locations in New Hampshire, four of which are on the Potvin's property. Its presence is closely monitored, because mile-a-minute can get out of control, quickly.

"It can grow six inches a day," says Gary Fish, a horticulturist with the Maine Department of Agriculture, Conservation and Forestry.

Fish says that mile-a-minute is very aggressive in staking out its territory, and will use its weight to drag down other plants.

"It will vine around plants, and it will also climb up plants," Fish says. "It is reminiscent of a lot of the vines that are out there that will cover plants over and basically outcompete those plants."

Doug Cygan, an invasive species coordinator for the New Hampshire Department of Agriculture, Markets and Food, holds out examples of the mile-a-minute vine's berries in Seabrook, New Hampshire. The plant's fruit becomes bright blue when it is mature and attracts birds, which help spread its seeds.
Caitlin Andrews
/
Maine Public
Doug Cygan, an invasive species coordinator for the New Hampshire Department of Agriculture, Markets and Food, holds out examples of the mile-a-minute vine's berries in Seabrook, New Hampshire. The plant's fruit becomes bright blue when it is mature and attracts birds, which help spread its seeds.

Mile-a-minute is native to Asia and is believed to have first been found at a Pennsylvania nursery in 1946. It can hitch a ride on nursery plants, which earned it a spot on Maine's "do not sell" list of plants. Its seeds are also spread by human activity and birds.

The invasive vine was first found in Maine in August by a resident of Boothbay Harbor. And after the Department of Agriculture publicly announced the discovery, people took notice.

"We've gotten many people saying, 'Oh, I've had this in my yard for years. I've been pulling it up all summer,'" says Lisa St. Hilaire, who works with Maine's natural areas program.

St. Hilaire says there were about 150 reported sightings after the Boothbay Harbor discovery was announced. But only two of those actually were confirmed to be mile-a-minute. That's because it has many lookalikes.

St. Hilaire says she got so many emails, her department came up with an identification chart to help citizen scientists know what to look for.

Back in New Hampshire, Doug Cygan is scouting around the Potvin's property, pulling long ropes of mile-a-minute out of the foliage.

Doug Cygan, an invasive species coordinator for the New Hampshire Department of Agriculture, Markets and Food, pulls a mile-a-minute vine from a tangle of plants in Seabrook, New Hampshire. The extremely invasive plant has only six known patches in New Hampshire, concentrated near the coast.
Caitlin Andrews
/
Maine Public
Doug Cygan, an invasive species coordinator for the New Hampshire Department of Agriculture, Markets and Food, pulls a mile-a-minute vine from a tangle of plants in Seabrook, New Hampshire. The extremely invasive plant has only six known patches in New Hampshire, concentrated near the coast.

Cygan says while it's concerning to find mile-a-minute here, there is evidence that it can be controlled.

The vine was found in the central region of New Hampshire in 2008, but was successfully eradicated using spot herbicide application. Cygan says he hasn't seen any new mile-a-minute plants there in the last 15 years — which he hopes means it's contained to these few spots in the Seacoast region.

"Things, you know, may occur here, we just haven't found them yet. Everything is definitely reliant on discovery," Cygan says.

And discovery, Cygan says, depends in part on the willingness of landowners to notify the state, when they find the mile-a-minute vine on their property.

Support for Deep Dive: Invasives is provided by Maine Audubon, Friends of Acadia and Coastal Maine Botanical Gardens.

Reporter Caitlin Andrews came to Maine Public in 2023 after nearly eight years in print journalism. She hails from New Hampshire originally.