Black dog-strangling vine, black swallowwort USDA PLANTS Symbol: CYLO11
U.S. Nativity: Exotic
Habit: Vines Forbs/Herbs
Vincetoxicum nigrum (L.) Moench

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Taxonomic Rank: Magnoliopsida: Gentianales: Asclepiadaceae
Synonym(s): Louis' swallow-wort
Native Range: Europe - south. (GRIN);

Appearance
Cynanchum louiseae is an herbaceous, twining, unbranched, perennial vine which can grow up to 6.5 ft. (2 m) in length.
Foliage
Leaves are opposite, dark green, oval, and shiny with entire margins. Leaves are from 3-4 in. (7.6-10.2 cm) long and 2-3 in. (5.1-7.6 cm) wide. A short petiole attaches the leaf to the vine.
Flowers
Clusters of 6-10 flowers bloom from June to September. Five lobed dark purple corollas are approximately 0.25 in. (0.6 cm) across and covered with short white hairs on the upper surface.
Fruit
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 hairs. The hairs allow the seeds to be readily dispersed by wind. Plants have rhizomes that sprout new plants.
Ecological Threat
Cynanchum louiseae readily invades upland areas. It tolerates a wide range of light and moisture conditions and can be found invading a wide variety of upland habitat types. It is native to Europe. The history of its introduction is uncertain, but it may have escaped from a botanical garden.

Identification, Biology, Control and Management Resources

Selected Images from Invasive.orgView All Images at Invasive.org


Infestation; Understory infestation
John M. Randall, The Nature Conservancy, Bugwood.org
Additional Resolutions & Image Usage

Seed(s); Dehiscing seeds
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage

Flower(s);
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage

Flower(s);
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage

Flower(s);
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage

Fruit(s);
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage

Fruit(s);
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage

Foliage;
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage

Seed(s);
Bruce Ackley, The Ohio State University, Bugwood.org
Additional Resolutions & Image Usage

Seed(s);
Bruce Ackley, The Ohio State University, Bugwood.org
Additional Resolutions & Image Usage

Plant(s);
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage

Infestation;
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage

EDDMapS Distribution:
This map is incomplete and is based only on current site and county level reports made by experts and records obtained from USDA Plants Database. For more information, visit www.eddmaps.org
 


State(s) Where Reported invasive.
Based on state level agency and organization lists of invasive plants from WeedUS database.

U.S. National Parks where reported invasive:
Weir Farm National Historical Park (Connecticut)



Invasive Listing Sources:
Connecticut Invasive Plant Working Group
Hoffman, R. & K. Kearns, Eds. 1997. Wisconsin manual of control recommendations for ecologically invasive plants. Wisconsin Dept. Natural Resources, Bureau of Endangered Resources. Madison, Wisconsin. 102pp.
Invasive Plant Council of New York State
Jil M. Swearingen, Survey of invasive plants occurring on National Park Service lands, 2000-2007
John Randall, The Nature Conservancy, Survey of TNC Preserves, 1995.
Mid-Atlantic Exotic Pest Plant Council, 2005
New Hampshire Invasive Species Committee. 2005. Guide to Invasive Upland Plant Species in New Hampshire. New Hampshire Department of Agriculture,  Markets and Food Plant Industry Division and New Hampshire Invasive Species Committee.