Toxic Parts:
pyrrolizidine alkaloids
Flower Color:
  • flower color
woodlands, waterside, meadows, haybales

Time of Greatest Risk


Geographical Distribution

Ragwort distribution - United States

Related Species


Senecio jacobaea

Tansy Ragwort, Golden Ragwort, Stagger Wort, Stinking Willy, St James Wort
6/ 10
Ragwort (Jacobaea vulgaris or Senecio jacobaea) is a biennial (sometimes annual or perennial) herbaceous flowering plant. It is considered an invasive weed in most parts of the world and is well known for its poisonous effects on livestock over the years.

Ragwort Toxic Components

Horses are particularly sensitive to the poisonous effects of ragwort, and tend to avoid it; however if horses are turned out in pastures with no available forage or if provided hay contaminated with ragwort, they are more likely to ingest it. Ragwort contains pyrrolizidine alkaloids (jacobine, eruifoline, and senecionine) which causes pyrrolizidine alkaloid toxicity, often leading to liver failure when consumed over a prolonged period of time. Unfortunately, clinical signs take a while to show, which is usually after liver damage is advanced and irreversible.

What Ragwort Looks Like

Ragwort is recognized by its daisy-like, 13 petal, yellow flowers. Ragwort has erect, unbranched stems that grow up to 4 feet in height and branch near their tips. As a biennial, tansy ragwort spends the first year in the rosette stage with dark green basal leaves that appear ruffled. During the second year, one or two flowering stems form.


  • Lethargy
  • Aimlessly Wandering
  • Depression
  • Chronic Weight Loss
  • Photosensitization
  • Colic
  • Weakness
  • Listlessness
  • Jaundice
  • Diarrhea
  • Head Pressing
  • Blindness
  • Circling


MANUAL CONTROL: Ragwort can be controlled through hand pulling plants from the soil. However the entire root needs to be removed in order to prevent regrowth. Plants are easiest to remove after plants have bolted but prior to flowering, and following a rainfall when the soil is moist and easier to break through.

MECHANICAL CONTROL: Mowing is not an effective method of control for ragwort.

CHEMICAL CONTROL: Research results show that tansy ragwort can be controlled with 2,4-D (low volatile ester or emulsifiable acid) at 0.5-1.0 kg pounds active ingredient per acre, or by dicamba at 0.23 to 0.5 kg active ingredient per acre. Tansy ragwort should be sprayed in the rosette stage. Both herbicides will injure or kill legumes.

BIOLOGICAL CONTROL: The tansy ragwort flea beetle, Longitarsus jacobaeae, larvae and adults are attack tansy ragwort. Larvae feed on and within the roots and the adults feed on leaves. The ragwort seedhead fly, Botanophila seneciella, larvae feed within seedheads, often destroying all of the developing seeds. The cinnabar moth, Tyria jacobaeae, caterpillars can completely defoliate tansy ragwort.