Conservationists are asking people to look for an invasive vine that harms the monarch butterfly population and the ecosystem in general. It is called the strangling vine of dogs and has now been found in New Brunswick.
Monarch butterflies have distinctive orange and black markings with white dots on the edges of the wings. The sightings of monarchs are a sure sign that summer is approaching, as they migrate back to Atlantic Canada after wintering in Mexico.
Butterflies depend on the dawn for reproduction. They lay their eggs on this common plant, and these eggs become caterpillars that only eat milk until they metamorphose into butterflies.
The strangling vine is part of the same family as the lettuce and looks too similar, according to Kristin Elton of the New Brunswick Invasive Species Council. Monarchs often confuse it with milk when they lay their eggs, and when the eggs hatch there is nothing to eat.
“Caterpillars eventually die because they have no food,” Elton told Shift New Brunswick.
Vineyards strangling dogs taking control of a forest undergrowth. (David Nisbet / Invasive Species Center, Bugwood.org)
Also known as the European swallow must, the plant doesn’t actually strangle dogs, Elton said, but it has an extreme advantage over the native ecosystem.
It can grow up to two meters in height and produces intense pink or purple star-shaped flowers. It also produces long pods in the shape of a bean that contain seeds with spongy flakes that open and spread in the wind.
It is a very vigorous plant and will wrap around things and suppress other growths, he said. It also releases chemicals into the soil that prohibit the growth of other species.
“It’s a very impressive plant, it’s just one we don’t want here,” Elton said.
Dog strangling vine climbing a tree. The plant produces chemicals in the soil that prevent other plants from growing around it. (John M. Randall / The Nature Conservancy, Bugwood.org)
In addition, deer often avoid this plant because it produces toxic sap.
And even though it doesn’t have nine lives, it’s harder to kill than a normal weed.
Elton said that if you see it around your property, dig it up, but don’t just throw it in your compost pile. Even after digging, you can still spread the seeds. Therefore, it must be kept in a black, well-sealed garbage bag and left in the sun for a few days to decompose.
According to the Nature Conservancy of Canada, the vineyard arrived in Canada with European settlers about 120 years ago.
It has generally been found in southern Ontario, but has recently been seen in New Brunswick, including Saint John. It has also been detected in Nova Scotia, Elton said, but the exact extent of its spread is unknown.
“We’re missing a lot of data. We know they’re here, but we really don’t know exactly how far they’re,” he said.
That’s why it appeals to the public to find out what the plant is like and report it via iNaturalist, an online tool and app.
“Just take a picture, upload it, it will show you where the location is. You can enter the information if you know what the plant is. If you’re not sure, it can do its magic. [artificial intelligence] thing and give you an idea of what species it is, “he said.