Hemp Dogbane

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