Swallow-wort (Vincetoxicum sp.) is a perennial vine with leaves that are oval to heart-shaped with pointed tips. Both of these species have tiny, star-shaped flowers in the spring/summer. The Black variety has dark purple flowers, while the Pale has light pinkish-yellow flowers. Long and large seed pods develop (much like those seen on milkweed plants) in the summer, and in the fall, the seed pod exterior dries out and releases flat brown seeds on fluffy white parachutes. Dead vines can be found in the winter with the dried seed pods still attached.
This species is common in the northwest part of Oakland County, but rare in other parts. Have you seen this species? Report it to us or on the MISIN website or smartphone app! Please include a photo to help with ID verification.
Swallow-wort grows rapidly, spreading via wind-blown seed and grows over native plants. The plants and roots of these species are toxic to mammals and some insect larvae.
There are multiple treatment options for invasive swallow-worts. These include both chemical and non-chemical options.
Non-chemical control methods:
– mowing or cutting: the plant is mowed using a heavy-duty mower or cut using hand-tools. Note: this methods may be effective for removing biomass and preventing seed production, but does not kill the plant.
– hand-pulling seedlings: small seedlings can be uprooted by hand. They should be placed in an area where they will not re-sprout, or in the garbage.
– seed-pod removal: removing the seed pods from swallow-wort plants can reduce the spread, but it will not kill the plant.
Chemical control methods:
– foliar spray: herbicide is sprayed onto the foliage of the plant. This is a common method used to treat large patches, often done by contractors.
– A homeowner’s guide to small-scale control of invasive swallow-worts [PDF of Guide]