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Ageratina altissima
Also called Richweed, Snakeroot, White Sanicle, White Snakeroot
White snakeroot is a poisonous perennial herb in the daisy family, native to eastern and central North America, and is the species once called Eupatorium rugosum. It is grown in gardens mainly as a dark-leaved cultivar and is usually a weed of shady woodland edges.
Ageratina altissima, also known as white snakeroot, richweed, or white sanicle, 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 some species once included in it have been moved to other genera.
A cultivar, sold under the name Eupatorium rugosum 'Chocolate', is grown in gardens for its dark-tinted foliage. The darkest color, which is a chocolate black, occurs in plants grown in a sunny location. The plants are shade-tolerant and do best in moist soils. More recently, the plant can be found under the correct species name.
White snakeroot contains the toxin tremetol; when the plants are consumed by cattle, the meat and milk become contaminated with the toxin. When milk or meat containing the toxin is consumed, the poison is passed on to humans. If consumed in large enough quantities, it can cause tremetol poisoning in humans. The poisoning is also called milk sickness, as humans often ingested the toxin by drinking the milk of cows that had eaten snakeroot. Although 80% of the plant's toxin, tremetone, decreases after being dried and stored away for 5 years, its toxic properties remain the same.
During the early 19th century, when large numbers of European Americans from the East, who were unfamiliar with snakeroot, began settling in the plant's habitat of the Midwest and Upper South, many thousands were killed by milk sickness. Notably, milk sickness was possibly the cause of death in 1818 of Nancy Hanks Lincoln, mother of Abraham Lincoln.
A. altissima is native to the central and eastern United States, from Texas in the west to Maine in the east and north, and Florida in the south. The species is also native in Canada in Quebec, Ontario, and the Northwest Territories. The species is adaptive to different growing conditions: it is found in woods and brush thickets and also in shady areas with open bare ground, and it can be weedy in shady landscapes and hedgerows.
Sticky snakeroot · Ageratina glabrata · Privet Leaved Agertina · Snakeroot
Text excerpted from the Wikipedia article Ageratina altissima by its contributors, under CC BY-SA 4.0; the excerpts and the care summary drawn from them are shared under the same licence.
The care summary was written by AI (Claude, Anthropic) from the sources on this page, with general growing knowledge where they are silent. Check before relying on it.
Life form, climate and native range: World Checklist of Vascular Plants, Royal Botanic Gardens, Kew (CC BY 3.0), reformatted; see Plants of the World Online.
