Culture
Easily grown in moist soils in full sun to part shade. Invasive plant that will aggressively spread in the landscape by rhizomes and self-seeding.
Noteworthy Characteristics
Vincetoxicum hirundinaria, commonly called white swallow-wort or pale swallow-wort, is a rhizomatous herbaceous perennial which is native to cliffs, slopes and rocky outcrops in Europe and southwestern Russia. It has escaped gardens and naturalized in parts of New York, Michigan and Ontario. This is an invasive, upright, ultimately twining, vine-like plant that grows to 3-6’ per season. If allowed to naturalize unimpeded by any control measures, it can quickly cover open forested areas, forest margins, grasslands, pastures, slopes and roadways with tangled masses of foliage that shade, suppress growth and sometimes totally choke out nearby native plants in the course of often forming a dense monoculture.
Opposite, short-stalked, ovate to lanceolate leaves (to 5” long) have entire margins and rounded to cordate bases. Flowers (to 1/2” wide) in umbelliferous cymose inflorescences feature (a) a corolla of 5 basally-fused greenish-white petals, (b) a calyx of 5 fused, triangular, sharp-pointed sepals and (c) a 5-parted corona containing 5 stamens. Flowers bloom from late May to mid July. Flowers are sometimes described as having the fragrance of rotten fruit. Fruit is a slender, 2” long, many-seeded follicle (seed pod) which splits open in late summer when ripe disbursing numerous seeds, each seed having a tuft of white hairs which allows the wind to lift and carry the seed, in a manner similar to milkweeds, to nearby areas where self-seeding will often occur.
In the State of Vermont, white swallow-wort is listed as a Class A Noxious Weed (defined as any noxious weed that is not native to Vermont, is not currently known to occur in Vermont, but is considered to be a serious threat to Vermont if introduced). Class A status is in large part attributable to (a) the established invasive nature of plants in the genus (introduced V. nigrum and V. rossicum are now much more widely established in the U. S. along the Atlantic Coast into the Midwest) and (b) the naturalization of V. hirundinaria in neighboring New York State.
Female monarch butterflies sometimes oviposit on swallow-wort plants instead of native species of milkweed, presumably because of similarity of appearance. Unfortunately, the resulting larvae cannot complete development on swallow-wort.
This plant has poisonous alkaloids in the roots and is considered to be poisonous to humans and animals.
Although originally included in the milkweed family (Asclepiadaceae), this vine has now been transferred to the dogbane family (Apocynaceae).
Synonymous with Cynanchum hirundinaria and Gonolobus hirundinaria.
Genus name comes from the Latin words vinco meaning conquer or outlast and toxicum meaning poison in possible reference to genus plants at one point being considered to be an effective antidote for snake poison.
Specific epithet comes from the Latin word hirundo meaning swallow in reference to the purported resemblance of its seedpod to the wing or tail of a swallow.
Common name of swallow-wort also refers to the resemblance of the seedpod to the wing or tail of a swallow.
Problems
No serious insect or disease problems.
Uses
Invasive species which is not recommended for planting.