Hemp Dogbane

Latin Name: Apocynum cannabinum

Identifying Characteristics:

  • 2-6 feet tall
  • Woody stem
  • Opposite leaves (2 leaves per node)
  • Smooth leaf edge
  • Flowers are arranged in clusters
  • Opposite venation on leaf midrib
  • Internal sticky milky sap
  • Underground rhizomes (horizontal stems)

Plant Longevity:

  • Perennial

Where Commonly Found:

  • Moist areas
  • Near streams
  • Roadsides
  • Waste areas
  • Pastures

Time of Most Concern:

  • Late spring up until early fall

Compound that Causes Concern:

  • Cardiac glycosides

Part of Plant Most Toxic:

  • Any green part of the plant or dried hay

Livestock Species Affected:

  • Cattle
  • Horses
  • Sheep
  • Goats

Pasture, Stored Feed, Both:

  • Both

Clinical Signs:

  • Rapid pulse
  • Dilated pupils
  • Convulsions
  • Vomiting
  • Death

Amount Needed to be Consumed for Clinical Signs / Death:

  • 0.5gm/kg (0.0023 oz/lb) of animal’s body weight
    • 2.3 oz in a 1,000 lb cow
  • 15 g (0.5 oz) of green leaves have been reported to cause death in some cows

Identifying Characteristics:

  • 2-6 feet tall
  • Woody stem
  • Opposite leaves (2 leaves per node)
  • Smooth leaf edge
  • Flowers are arranged in clusters
  • Opposite venation on leaf midrib
  • Internal sticky milky sap
  • Underground rhizomes (horizontal stems)

Plant Longevity:

  • Perennial

Where Commonly Found:

  • Moist areas
  • Near streams
  • Roadsides
  • Waste areas
  • Pastures

Time of Most Concern:

  • Late spring up until early fall

Compound that Causes Concern:

  • Cardiac glycosides

Part of Plant Most Toxic:

  • Any green part of the plant or dried hay

Livestock Species Affected:

  • Cattle
  • Horses
  • Sheep
  • Goats

Pasture, Stored Feed, Both:

  • Both

Clinical Signs:

  • Rapid pulse
  • Dilated pupils
  • Convulsions
  • Vomiting
  • Death

Amount Needed to be Consumed for Clinical Signs / Death:

  • 0.5gm/kg (0.0023 oz/lb) of animal’s body weight
    • 2.3 oz in a 1,000 lb cow
  • 15 g (0.5 oz) of green leaves have been reported to cause death in some cows
Toxic Plants Home Alsike Clover Black Cherry Buttercup Carolina Horsenettle Cocklebur Common Milkweed Cressleaf Groundsel Dallisgrass Eastern Black Nightshade Hemp Dogbane Jimsonweed Johnsongrass Perilla Mint Poison Hemlock Pokeweed Redroot Pigweed Star of Bethlehem Tall Fescue White Clover White Snakeroot Yew