Bracken fern
Pteridium aquilinum
- Plant type
- fern
- Settings
- Rangeland
- Risk
- Moderate risk Our rating from the cited sources.
- Review
- Not yet reviewed by a veterinarian.
Photos
Planned.
How to tell it
Broad, triangular fronds; plant 2 to 4 ft tall; burned-over ground, woodland and shady hillsides (ARS).
Look-alikes: Planned.
What to do on a site walk
- Limit time.
- Keep other forage available.
- Recheck burned units.
Why it matters
- Toxic principle
- Ptaquiloside; thiaminase
- Toxic parts
- All parts, green or in hay; young shoots highest
- Basis for our rating
- Chewgrass rating. ARS: cumulative poisoning in cattle and sheep after 2 to 4 weeks of steady grazing; goats not named.
Signs in goats
Fever, loss of appetite, bleeding, blood in urine or feces after weeks of eating it (ARS, cattle and sheep data).
If you think an animal has been poisoned, call your vet right away.
Season
Young shoots most toxic; often eaten late summer when other forage is short; common on burned-over ground (ARS).
Sources
- USDA ARS Poisonous Plant Research Lab: Western Bracken Fern
- Second source (poisonousplants.ansci.cornell.edu)
Links last checked: 2026-10-31