SWALLOW-WORT: MONARCH MENACE
Eco-gardening is at its best in The Monday Garden
October 9, 2005, Issue 191
An attractive “easy-to-grow” milkweed-family vine, black swallow-wort, was imported to New England from southern Europe in the late 1800’s as a garden ornamental and slowly began to spread west and south, across the egg-laying territory of North America’s awesome monarch butterflies, those mighty, tiny, flying jewels that migrate from as far north as Canada all the way to Mexico.
Picture: This wonderful photo, donated by a reader of The Monday Garden in Derry, New Hampshire, shows one of our lovely monarchs enjoying a local pond as the butterfly slowly makes its way to Mexico. photo: © 2005 Melissa Bolton
Black swallow-wort, in Latin Cynanchum louiseae (also known as Cynanchum nigrum, Vincetoxicum nigrum), is a bad, bad invasive plant, and we can say all the nasty things about it that apply to the other invasive perennial vines. It lurks along sunny borders and fences, smothering everything in sight. Fortunately, the vine only grow about 6 feet long, so black swallow-wort can’t pull down trees the way Asiatic bittersweet and porcelain berry do. Otherwise, the vine is nasty enough to justify its alias “Dog-Strangling Vine”. I’m sure a dog going through a fence could easily get tangled in it.
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Pictures: black swallow-wort on a fence in Stamford CT is strong enough to bend the fence’s finials. Bedford and North Streets, Stamford CT September 2005; swallow-wort getting established in a yew bush. 4th Street, Stamford CT September 2005