Swallow-wort (Vincetoxicum sp.)

Key Identification Features

• Oval, glossy, opposite leaves

• Small star-like flowers

  • Pale pink to maroon in pale swallow-wort

  • Deep purple to black in black swallow-wort

• Slim ‘bean pods’ with white fluff inside

Description

Swallow-wort is a climbing vine in the family Asclepiadaceae, the same family as the much-beloved milkweed found natively here in NY. Two species of swallow-wort have made their way to NY, pale swallow-wort (Vincetoxicum rossicum) and black swallow-wort (Vincetoxicum nigrum). The two share many similar features and are hard to distinguish most of the year, however, they are easily told apart by their flowers when present.

Unlike native milkweed, Swallow-wort is a climbing vine that will grow in dense patches smothering native plants. The leaves of swallow-wort are oval in shape with a pointed tip and reach lengths of about 3-4”. The leaves grow opposite, are glossy, and the leaves of pale swallow-wort tend to be a paler shade of green compared to black swallow-wort. Like milkweeds when the stems or leaves are broken milky-white latex will leak from the wound.

The flowers when present is a distinguishing feature in telling the two species apart. The flowers tend to be star-shaped and grow in clusters, similar to milkweed flowers. As the names suggests, black swallow-wort has dark purple to black flowers and pale swallow-wort has pale pink to maroon flowers. Black swallow-wort also has hairs on the flower petals giving them a velvety look.

Lastly, swallow-wort produces slender ‘bean’ pods with wind-dispersed seeds. The pods can grow up to 3” and when broken open are full of seeds with white fluff that aids in wind dispersal.

Native Range

Pale swallow-wort can be found natively in Ukraine and Southeastern Russia while black swallow-wort is native to the Mediterranean.

Habitat and Dispersion

Both species are typically found in upland areas such as rocky outcrops, fields, and woodlands. Both species can thrive in a variety of soils and tolerate some shade.

Swallow-wort thrives in disturbed areas and

Best Management Practices

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Additional Resources

NY Invasive Species Information