# black swallow-wort (*Vincetoxicum nigrum*) Black swallow-wort is a climbing plant with dark green leaves and pretty flowers. It can grow in many places and is often found in gardens and fields, making it a lovely addition to nature. - **Category:** [Plants](https://www.snappit.app/explore/categories/plant) - **Rarity:** Common - **Danger:** 2/5 · Low - **Snaps:** 5 - **Habitat:** Urban areas ![black swallow-wort](https://inaturalist-open-data.s3.amazonaws.com/photos/1689479/medium.jpg) Photo: jacinta lluch valero, CC BY-SA 4.0 · [iNaturalist](https://www.inaturalist.org/photos/1689479) ## Appearance The black swallow-wort is a twining perennial vine with slender stems and glossy, dark green oval leaves arranged in pairs. It has clusters of tiny, star-shaped flowers that are dark purple to nearly black, often appearing brownish-purple up close, making them distinct from other vines. ## Taxonomy - **Kingdom:** Plantae - **Phylum:** Tracheophyta - **Class:** Magnoliopsida - **Order:** Gentianales - **Family:** Apocynaceae - **Genus:** Vincetoxicum ## Interesting facts - Even though it looks like milkweed, monarch butterfly caterpillars can't survive eating its toxic leaves! - Its seeds have feathery parachutes, like dandelions, allowing them to fly long distances in the wind! - One plant can make over 2,000 seeds in a year, helping it spread super fast! - This plant is nicknamed 'dog-strangling vine' because it can completely cover and choke out other plants! ## Special abilities - **Smothering Growth:** Black swallow-wort can rapidly climb and smother native vegetation, using its twining stems to outcompete other plants for sunlight and space. - **Explosive Seeds:** Black swallow-wort has explosive seed pods that release hundreds of parachute-like seeds, helping it spread far and wide with the wind. - **Monarch Mimicry Trap:** Black swallow-wort produces chemicals similar to milkweeds, tricking monarch butterflies into laying eggs, though their larvae cannot survive. ## Measurements & details - **Height:** 100-200 cm - **Spread:** 50-150 cm - **Flower Size:** 0.5-0.8 cm - **Bloom Season:** Summer - **Edible:** No - **Toxicity:** High - **Lifecycle:** Perennial - **Pollination Method:** Insect ## Ecological connections - **Eaten by:** [Monarch butterfly](https://www.snappit.app/explore/monarch-butterfly) (*Danaus plexippus*) — Larvae attempt to eat leaves, but cannot survive due to toxicity. - **Eats:** Swallow-wort moth (*Hypena opulenta*) — Larvae specifically feed on the plant, used as a biocontrol agent. - **Pollinates:** House fly (*Musca domestica*) — Visits flowers, aiding in pollination. ## Traits - [Climbing/Vine](https://www.snappit.app/explore/traits/climbing-vine): Climbing or vine plants are characterized by a growth habit that allows them to ascend upwards by twining, tendrils, or adhesive roots. - [Aromatic](https://www.snappit.app/explore/traits/aromatic): Aromatic plants produce and emit fragrant volatile organic compounds, often for defense or to attract pollinators. - [Flowering](https://www.snappit.app/explore/traits/flowering): Flowering plants are any plants that produce flowers as part of their reproductive cycle. - [Summer Blooming](https://www.snappit.app/explore/traits/summer-blooming): Summer blooming plants produce their flowers during the summer season, often providing vibrant color when many other plants have finished. - [Pollinator Magnet](https://www.snappit.app/explore/traits/pollinator-magnet): Describes plants that are particularly attractive and beneficial to a wide range of pollinating organisms. - [Poisonous](https://www.snappit.app/explore/traits/poisonous): Poisonous organisms produce toxins that can cause harm when ingested, inhaled, or absorbed through contact. - [Urban Friendly](https://www.snappit.app/explore/traits/urban-friendly): This habitat trait indicates species that can coexist with humans in urban and suburban environments, utilizing man-made structures and green spaces. - [Invasive](https://www.snappit.app/explore/traits/invasive): Invasive species are non-native organisms that cause harm to the environment, economy, or human health. ## Collections - [Plants](https://www.snappit.app/explore/collections/plants) ## Safety **Danger:** 2/5 · Low Always wash your hands after touching plants, just to be safe! ## Frequently Asked Questions ### How to identify black swallow-wort? Start with the whole plant, then compare leaf arrangement, leaf edges, stems and any flowers or fruit. Opposite leaves grow in pairs; alternate leaves come one at a time along the stem. These details tell you far more together than a single green leaf does. Plant Identifier: upload a photo and compare the visible details. ### How tall is black swallow-wort? 100-200 cm ### How wide does black swallow-wort spread? 50-150 cm ### How big are the flowers on black swallow-wort? 0.5-0.8 cm ### When does black swallow-wort bloom? Summer ### Is black swallow-wort edible? No ### Is black swallow-wort toxic? High ### What is black swallow-wort's lifecycle? Perennial ## Where to spot - [Squantum Point Park](https://www.snappit.app/guides/places/squantum-point-park) — Massachusetts, US · Nature Reserve - [Arlington Center Historic District](https://www.snappit.app/guides/places/arlington-center-historic-district) — Massachusetts, US · Historic District - [Bellport Village Historic District](https://www.snappit.app/guides/places/bellport-village-historic-district) — New York, US · Historic District - [Boston Consumptives Hospital](https://www.snappit.app/guides/places/boston-consumptives-hospital) — Massachusetts, US · Historic Site - [Pierce Farm Historic District](https://www.snappit.app/guides/places/pierce-farm-historic-district) — Massachusetts, US · Historic District - [Stone Street Historic District](https://www.snappit.app/guides/places/stone-street-historic-district) — New York, US · Historic District [View all places to see black swallow-wort](https://www.snappit.app/guides/where-to-see/black-swallow-wort) ## More Plants - [white snakeroot](https://www.snappit.app/explore/white-snakeroot) (*Ageratina altissima*) - [tree-of-heaven](https://www.snappit.app/explore/tree-of-heaven) (*Ailanthus altissima*) - [western sword fern](https://www.snappit.app/explore/western-sword-fern) (*Polystichum munitum*) - [common milkweed](https://www.snappit.app/explore/common-milkweed) (*Asclepias syriaca*) --- Source: [Black Swallow-wort: Facts & Places to See — Snappit](https://www.snappit.app/explore/black-swallow-wort)