Black Swallow-wort, Dog-strangling Vine, Louis' Swallow-wort
Vincetoxicumnigrum

Synonym:Alexitoxicon nigrum

Synonym:Antitoxicum nigrum

Synonym:Asclepias nigra

Synonym:Cynanchum louiseae

Synonym:Cynanchum nigrum

Category
Perennials
Vines and Climbers

Water Requirements
Average Water Needs; Water regularly; do not overwater

Sun Exposure
Full Sun
Sun to Partial Shade

Foliage
Herbaceous

Foliage Color

Height
4-6 ft. (1.2-1.8 m)

Spacing
24-36 in. (60-90 cm)

Hardiness
USDA Zone 4a: to -34.4 °C (-30 °F)
USDA Zone 4b: to -31.6 °C (-25 °F)
USDA Zone 5a: to -28.8 °C (-20 °F)
USDA Zone 5b: to -26.1 °C (-15 °F)
USDA Zone 6a: to -23.3 °C (-10 °F)
USDA Zone 6b: to -20.5 °C (-5 °F)
USDA Zone 7a: to -17.7 °C (0 °F)
USDA Zone 7b: to -14.9 °C (5 °F)
USDA Zone 8a: to -12.2 °C (10 °F)
USDA Zone 8b: to -9.4 °C (15 °F)
USDA Zone 9a: to -6.6 °C (20 °F)
USDA Zone 9b: to -3.8 °C (25 °F)

Where to Grow

Danger
Parts of plant are poisonous if ingested

Bloom Color
Rose/Mauve

Bloom Characteristics

Bloom Size

Bloom Time
Late Spring/Early Summer
Blooms repeatedly

Other details
May be a noxious weed or invasive

Soil pH requirements
5.6 to 6.0 (acidic)
6.1 to 6.5 (mildly acidic)
6.6 to 7.5 (neutral)

Patent Information
Non-patented

Propagation Methods
Self-sows freely; deadhead if you do not want volunteer seedlings next season

Seed Collecting
Bag seedheads to capture ripening seed
Allow pods to dry on plant; break open to collect seeds
Allow seedheads to dry on plants; remove and collect seeds
Properly cleaned, seed can be successfully stored