Black Swallow-Wort Control 

A Toxic Invader 

 A species of concern that threatens Northern Michigan's environmental quality is black swallow-wort (Cynanchum louiseae). This species is an invasive noxious vine, identifiable by its opposite, glossy leaves and five pointed, star shaped flowers. It is a cause for concern for several reasons. Firstly, its roots are toxic to people and mammals if ingested. Secondly, it is allelopathic; it emits chemicals into the soil that inhibits the growth of native plant species. Thirdly, it is toxic to pollinators such as Monarch butterflies, which mistake the plant for milkweed and unwittingly lay their eggs on the deadly plant. After the caterpillars hatch, the ingestion of this plant kills them. Finally, it forms dense infestations, which outcompetes and smothers native plants. These infestations become extremely costly to remove if left alone. Despite a limited distribution in Northern Michigan, it has established itself in the City of Petoskey, and has the capability of spreading beyond the city if left unchecked. The CAKE CISMA has worked for several years with limited funding to attempt to treat this species and curb its spread. 

Cost-Shared Control for Private Landowners

Through a grant project funded by the Michigan Invasive Species Grant Program, the CAKE CISMA is offering cost-shared control of swallow-wort infestations for private landowners at a 50% rate through the months of May - July, 2020. If you are seeking confirmation that you have swallow-wort, please contact us at (231)-533-8363 ext. 5 or 

Partnering with Petoskey City Parks

To protect the environmental quality of Petoskey's public lands, the CAKE CISMA applied to a grant from the Petoskey and Harbor Springs Area Community Foundation in 2019 to control swallow-wort in public areas that are enjoyed by people and used by wildlife as habitat. The proposal was successful, and the CAKE CAKE CISMA is now partnering with the Petoskey Parks and Recreation department to fund the treatment of black swallow-wort in three city parks in the summer of 2020. The parks include Bayfront Park, Winter Sports Park, and the Bear River Valley Recreation Area. We are thankful to the Community Foundation for this wonderful opportunity. This project will help to protect our native pollinators, such as the monarch butterfly. For details on this project, contact CAKE CISMA coordinator Benjamin VanDyke at 

Do you have Black Swallow-Wort on your property?

The CAKE CISMA is offering free surveys and a 50% cost-shared rate to provide swallow-wort control. Property owners can contact CAKE CISMA

Coordinator Benjamin VanDyke at either 
231.533.8363 or by email at to learn more.

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231-533-8363 ext. 5

4820 Stover Road

Bellaire, MI 49615

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© 2023 CAKE CISMA. Funding provided by the Michigan Invasive Species Grant Program.