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Black Swallow-Wort Initiative 2024

Promoting healthy, biodiverse habitats in Northern Michigan

Invasive species disturb the balance of ecosystems and are second only to habitat loss in their systematic threat to native wildlife. While many invasive plants are already present in our service area, we focus our efforts on the plants we can still control. That's where the black swallow-wort comes in. CAKE CISMA has been working to stop the spread of this emerging invasive plant in northern Michigan for several years, but we can't do it alone. We need help from our community as we work together to collectively manage black swallow-wort. 

What is Black Swallow-wort?

Black swallow-wort is an invasive, herbaceous, perennial vine in the milkweed family that is native to Europe.  This species is of special concern to us here in Northern Michigan because of its negative environmental impacts and still limited distribution. 

Environmental Impacts

  • Black swallow-wort overtakes and suppresses other vegetation, reducing species diversity, wildlife habitat, and native plant populations. 

  • Black swallow-wort is toxic to many insects including monarch caterpillars. It can be a population sink for Monarch butterflies and may outcompete the Monarch’s preferred host, common milkweed.

  • Black swallow-wort roots are toxic to mammals, including livestock


Black Swallow-wort Initiative Goals:


Swallow-wort is not widespread in Charlevoix, Antrim, or Kalkaska counties. We believe if we act now, we may be able to eradicate small outlier populations in these areas, but we need your help finding them. 

Engage Community

One challenge with invasive species is lack of awarness. Often, by the time the general population knows about an invasive it's too widespread to control. Learn about swallow-wort and help us spread the word, not the species. 


Black swallow-wort was first discovered in Northern Michigan in Petoskey.  The population there has grown and we are working to contain it before it spreads further. 

We need your help - get involved! 

Report potential infestations

Public reports help us find undocumented infestations so we can manage them sooner. If you see swallow-wort please let us know. If possible, include a photo of the plant and its location with your report - it helps a lot!

Manage swallow-wort on your land

Check out our basic management recommendations linked below. CAKE CISMA offers free chemical treatment of swallow-wort to residents in Charlevoix, Antrim, & Kalkaska counties as well as case-by-case management in Emmet County. 


Pull the pods: pull and dispose of swallow-wort seeds in the garbage when they form in late July. The seeds are dispersed by the wind, so you'll be preventing new infestations.

Identification Tips: 

Look for black 5-petal flowers in June/July. The flowers are small. 


Skinny, smooth, green seedpods form in July/August, turn yellow then split open in the fall. 

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Twine around itself and may climb small shrubs or bushes. Vines always have clear, watery sap. 

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