Why do we care so much about removing these plants?
As you probably know, the population of monarch butterflies in Massachusetts has declined
significantly in the past decade. They, like bees, are important pollinators in our enverionment. Common milkweed is the only plant that monarch larvae can eat, and loss of meadow habitat in the state has led to a loss of available milkweed to feed the caterpillars.
To make their situation worse, black swallow-wort appears to the female monarch butterfly to be a fine plant on which to lay her eggs. It is in the same family as common milkweed. However, when the monarch larvae hatch, they do not recognize the plants as food, and they starve to death.
Please look for the black swallow-wort vines, and remove them, or at least their pods.
Look in your yards and the edges of fields, parks and parking lots for small purple flowers that turn to pea-like pods hanging from vines with glossy leaves. Then, dig up, pull up, cut down, or as a last resort just pull off the pods – and get the plants and pods into trash bags and dispose as trash – before the pods burst!
If you aren’t familiar with the plant, see the Black Swallow-Wort flyer.
More information is also at the Newton Conservators website.