white snakeroot
Ageratina altissima
Nancy Hanks Lincoln, the mother of Abraham Lincoln, died in 1818 from milk sickness after drinking milk from a cow that had grazed on this toxic plant.
- Scientific name
- Ageratina altissima
- Taxonomy
- Plantae › Tracheophyta › Magnoliopsida › Asterales › Asteraceae › Ageratina
- IUCN Red List status
- Least Concern
- Population trend
- stable
- Biome
- forest
- Habitat
- Rich, moist woods, thickets, shady slopes, and forest openings.
- Diet
- Autotrophic (photosynthesis)
- Range
- Eastern North America, Central North America
- Size
- 30 to 150 cm (1 to 5 feet) tall
- Lifespan
- Perennial (rhizomes can persist for many years)
- Active
- diurnal
- Threats
- Habitat loss from urban development and displacement by aggressive invasive plants.
- Safe to approach?
- This plant is highly toxic if ingested due to the cumulative toxin tremetol. It is safe to touch and observe from a distance, but absolutely do not consume any part of it. Keep grazing pets and livestock away from it. If ingested by humans or animals, seek immediate medical or veterinary assistance.
Ageratina altissima , also known as white snakeroot , richweed , white sanicle , or tall boneset , is a poisonous perennial herb in the family Asteraceae, native to eastern and central North America. An older binomial name for this species is Eupatorium rugosum , but the genus Eupatorium has undergone taxonomic revision by botanists, and a number of the species that were once included in it have been moved to other genera.
Photo: Douglas Goldman, CC-BY-SA, via iNaturalist
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