NORTHPORT, Maine — Last summer, two very unwelcome out-of-towners put down roots in the village of Bayside, until locals got rid of them in the dead of night.

It wasn’t a matter of xenophobia. It was a matter of safety, according to town officials who are asking residents to keep a close eye out this summer to see if there’s been a return of the intruder: giant hogweed.

The noxious plant’s sap is an extreme irritant. When skin touches the sap, the results can be painful blisters and burns that can cause permanent scarring. Contact with eyes can cause blindness.

“Be on the lookout. Don’t touch it,” Denise Lindahl, a selectman, said Monday. “Just let us know and we’ll deal with it.”

When the large plants were spotted last summer on George Street, the main route for Bayside village, it caused consternation for many who live in town.

“I was very concerned,” said Dan Webster, adding that he’s staying away from all plants with little white flowers. “I wouldn’t touch any of these plants now. I’m afraid. The symptoms don’t sound at all fun.”

Giant hogweed is a native of the Caucasus region of Asia, and can grow up to 14 feet tall or higher. Its leaves are several feet long and stems measure as much as 4 inches thick. But the flowers are the plant’s most remarkable aspect: white clusters that can measure 2 feet across.

Because of those flowers, hogweed can be mistaken for angelica or cow parsnip. But those plants do not grow as big.

“It’s a really spectacular and very large plant,” Ann Gibbs, state horticulturist with the Maine Department of Agriculture, told the BDN last fall.

At that time, the agency had documented at least 20 sites around the state with giant hogweed, including the Bayside site. About half of the sites are located in Hancock County, including several in Acadia National Park.

The plant used to be popular with estate owners who searched for exotic plants from around the world to fill their ornamental gardens, experts have said.

Now, state and federal agencies are working to eradicate giant hogweed, which generates a large crop of seeds each year, making that work a challenge.

Lindahl is hoping that if giant hogweed is spotted again in Bayside, or elsewhere in Northport, landowners or concerned gardeners won’t take it upon themselves to cut down the plant, as happened last year.

“Oh my God,” the nurse recalled thinking when she learned of the nocturnal hatchet job. “Professionals have to come in, and have the right gear on, so they don’t touch it.”

She said that she did not hear of any giant hogweed-related injuries last summer, though the Maine Department of Agriculture gave a heads-up to Waldo County General Hospital just in case.

But she did hear that some residents think it’s a pretty plant and “we shouldn’t do anything to it.”

She and other town officials vehemently disagree.

“We’re trying to nip it in the bud this year,” Lindahl said.

Northport residents who spot giant hogweed can call the town office at 338-3819.

Around Maine, sightings should be reported to the Maine Department of Agriculture at 287-3891.