Pale swallowwort looks similar to a related species, black swallowwort. The two plants have similar leaves and growth habit, but they can be distinguished by their flowers. The petals of black swallowwort are much darker -- a purple that is nearly black. Black swallowwort petals are also slightly fuzzy, and they are shorter and wider than those of pale swallowwort.
Pale swallowwort was introduced from Europe in the 19th century. It is an invasive plant -- as a vine, it can grow over other vegetation, strangling or shading out native plants. More on this topic from Invasive Plant Atlas of New England.
- Synonyms: Vincetoxicum rossicum
- Family: dogbane (Apocynaceae)
- Habitat: roadsides, fields, edges of woods, rocky areas
- Height: 3-5 feet
- Flower size: 1/8 inch across
- Flower color: dark red, dark pink, or yellow-brown
- Flowering time: June to September
- Origin: Europe
Swallowwort have seedpods similar to milkweed pods. The pods persist through winter.