Pale Swallow-wort

Pale swallowwort

Cynanchum rossicum (Vincetoxicum rossicum)

*Detected in Michigan*

Report this species:

Use the Midwest Invasive Species Information Network (MISIN) online reporting tool 

- Or - download the MISIN smartphone app and report from your phone - http://www.misin.msu.edu/tools/apps/#home

 

Clusters of small, pale swallow-wort flowers are pink and shaped like stars.

Leslie J. Mehrhoff, University of Connecticut, Bugwood.org 

A green pale swallow-wort vine twines up a twig.

Leslie J. Mehrhoff, University of Connecticut, Bugwood.org 

Three long, slender green seed pods resembling those of the milkweed plant.

Leslie J. Mehrhoff, University of Connecticut, Bugwood.org 

Identification:

  • An herbaceous, twining perennial vine growing up to 7 feet in length
  • Leaves are shiny medium-green to yellow and oval to heart-shaped with a pointed tip
  • Small, star-shaped flowers are pale pink to reddish brown with 5-petals and grow in clusters of 6-10 blooms
  • Seed pods are milkweed-like and full of flat, brown seeds covered in fine, white hairs
  • Unlike black swallow-wort, pale swallow-wort plants have no rhizomes and grow in clumps with  many stems

Habitat: Pale swallow-wort is an upland vine tolerant of shade, sun and a variety of soil moistures.  It is generally found in disturbed areas including old fields, woodlands and brushy areas.  Pale swallow-wort can also invade perennial crops including pastures, tree farms and no-till fields.  Like black swallow-wort, it thrives in the shallow soils and limestone bedrock of alvar areas and poses a threat to these rare ecosystems.  

Native Range: Ukraine and Southwestern Russia

U.S. Distribution:  New England, Wisconsin, Indiana.  Also in Toronto, Canada.

Local Concern: Pale swallow-wort can form extensive patches that crowd out native plants and disrupt ecosystems.  Seeds are carried on the wind or transported by water.  Roots are toxic to mammals, including livestock.  Plants are toxic to many insect larvae including monarch caterpillars. 

MORE INFORMATION:

Pale Swallow-wort Invasive Species Alert - Printable PDF 

Best Control Practice Guide for Black and Pale Swallow-worts - This document provides in-depth information about black and pale swallow-worts in the state of Michigan including identification, distribution, management and control options.