06/10/2026
It’s Black Swallow Wort Season!
Have you noticed this plant in your yard? Black Swallow Wort (BSW) is an invasive species in Massachusetts, and removing it is a huge help in preserving our healthy, native ecosystems!
How you dispose of it depends on the flowers:
If the flowers haven't opened yet: Pull them now! Because BSW is a fast-growing vine that chokes out native plant species.
OR
If the flowers are already opened: the flowers will produce seed pods, and when the pods open, the seeds will spread! Pull the plants, place them in a sealed black plastic trash bag, and leave the bag in a sunny spot for at least 10 days to dry out ("desiccate"). Once dried, dispose of the bag in your regular trash.
Have questions? Reach out to [email protected]
You can also check out the City's website to learn more about Knotweed and other invasive species in Watertown: www.watertown-ma.gov/1156/Invasive-Plants
Here is a video that has a lot of information: https://wildcohasset.org/black-swallow-wort-id
[Image description: words "Black Swallow-Wort. Be aware of Black Swallow-Wort, a common invasive plant species around Watertown, and why we are asking residents to remove it from their yard." and photos of the plant]
