The swallow-worts (also called dogstrangling vine) are perennial, herbaceous, twining vines. The two species of principal concern in North America are black and pale swallow-wort. Black swallowwort is native to southwest Europe; pale swallow-wort is native to Ukraine and parts of Russia. Both were introduced to North America in the 1800s as potential ornamental plants.
Although swallow-worts are not yet well established in Indiana, their vines are highly invasive and grow vigorously, quickly twining around, and will climb anything nearby such as trees and shrubs or even man-made structures. This can overwhelm nearby plants by physically shading them, weighing them down, causing stem breakage, and forcing them to compete for moisture and nutrients.
At the time of writing, nine counties in central and northern Indiana reported small populations of black swallow-wort ranging in size from 10 square feet to 2,500 square feet of the infested area. Along Indiana’s border, two Michigan counties and the Chicago area report significant populations of black swallow-wort. No records of pale swallow-wort have been reported for Indiana. Two Michigan counties bordering northern Indiana and a central Illinois county are the nearest reported populations of pale swallow-wort.
This publication, Invasive Plant Series: Swallow-worts, aids in identifying these swallow-worts and provides management recommendations focused on prevention of spread, early detection, and properly timed and targeted control measures.
Invasive Species, Playlist, Purdue Extension YouTube Channel
Invasive Plants Threaten Our Forests Part 1: Invasive Plant Species Identification, Webinar, Purdue Extension – Forestry and Natural Resources YouTube Channel
Invasive Plants Threaten Our Forests Part 2: Control and Management, Webinar, Purdue Extension – FNR YouTube Channel
Indiana Invasive Species Council
Report Invasive, Purdue Extension
Invasive plants: impact on environment and people, The Education Store, Purdue Extension resource center
Invasive Plant Species Fact Sheets: Poison Hemlock, The Education Store
What are invasive species and why should I care?, Got Nature? Blog, Purdue Extension – Forestry and Natural Resources
Ronald Rathfon, Regional Extension Forester Southern Indiana Purdue Agriculture Center (SIPAC)
Purdue Department of Forestry and Natural Resources