black swallowwort

Gentianales > Asclepiadaceae > Cynanchum louiseae Kartesz & Gandhi
Synonym(s): Louis' swallow-wort

Black swallowwort is an herbaceous, twinning, perennial vine. Leaves are opposite, dark green, oval, shiny, entire, 3-4 in. (7.6-10.2 cm) long and 2-3 in. (5.1-7.6 cm) wide. Flowering occurs in June to July, when dark purple, 5-petaled, star-shaped flowers appear in clusters. Flowers are approximately 0.25 in. (0.6 cm) across and covered with white hairs. Fruit are pods, similar to milkweed pods, which are slender, 2-3 in. (5.1-7.6 cm) long and split to reveal small seeds with tufts of white hair. The hair allows the seeds to be readily dispersed. Plants have rhizomes that sprout new plants. Black swallowwort invades upland areas with a wide range of light and moisture conditions. Black swallowwort is native to Europe and escaped from a botanical garden in Massachusetts.


Identification, Biology, Control and Management Resources

  • Weeds of the Week - USDA Forest Service, Northeastern Area, Forest Health Protection

Selected Images from Invasive.org

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Seedling(s);
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
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Feature(s); Comparision of flowers of Cynanchum louiseae (top) and Cynanchum rossicum
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
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Flower(s);
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
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Fruit(s);
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
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Feature(s); Twining vines
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
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Seed(s); Dehiscing seeds
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
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Infestation;
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
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Infestation;
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
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Diagram or Graphic; Britton, N.L., and A. Brown. 1913. Illustrated flora of the northern states and Canada. Vol. 3: 36.
USDA PLANTS Database, USDA NRCS PLANTS Database, Bugwood.org
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Invasive Reference(s):

Check Invasive.org for most current lists.
  • Connecticut - Noxious Weed Law
  • Massachusetts - Noxious Weed Law
  • New Hampshire - Noxious Weed Law
  • Vermont - Noxious Weed Law
  • Invasive Plant Atlas of New England


External Links


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