Pull Out Black Swallow-wort Weed and Save the Monarch Butterfly

Have you seen the pea-like pods of the black swallow-wort climbing up fences and plants all over Newton? We’re asking for your help to remove them.

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, to the female monarch butterflies, black swallow-wort appears to be a fine plant on which to lay their 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.

A week ago, our summer interns Iris and Bennett spent two hours pulling it off the fence along Centre Street by Crystal Lake–just in time before the pods opened and released hundreds of fluffy wind-borne seeds, which would have increased the infestation.

Bennett and Iris and the rest of the Conservators’ invasives-removal team cannot be everywhere, so we’re asking for your help in looking for the plants and removing them, or at least their pods.

Please look in your yards and the edges of fields, parks and parking lots for 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 at  http://bit.ly/2ubL34A

More information is also at the Newton Conservators website:  http://www.newtonconservators.org/controlling_invasives.htm


If you want to do more to help the monarchs, plant common milkweed (Asclepias syriaca) in a sunny spot in your garden. 

Don’t know where to get it? Stop by the Conservators’ table at either the Tuesday farmers’ market at Cold Spring Park or the Saturday farmers’ market at Elm Street, where you can get a package of seeds for a small donation. We hope to see you there!

Thank you!


Photo credit: Larissa Smith