White Snakeroot, Pretty but Poisonous

White Snakeroot (Agertina altissima) in bloom.
White Snakeroot (Agertina altissima) in bloom.

White Snakeroot is blooming all over the place. This pretty plant with small white flowers is a native of eastern woodlands in North America.

The plant grows naturally in the shade or partial shade and rich soils of the eastern forests. The slightly wrinkled dark green leaves look like those of nettle plants.

It is one of the few plants that bloom this late in the season, from September to frost.

I never really knew the name of the plant until this fall. The forest and woods are sometimes full of the tiny white flowers glowing in the shade.

I remember this plant from my childhood. My friends and I would use this plant for ‘cooking’ in our play kitchens. Little did we know it was poisonous.

The plant is poisonous to horses, cows, sheep and goats. Both the milk and the meat of these animals becomes poisonous after eating White Snakeroot. Many thousands of European-American settlers died after drinking the milk of cows who had eastern White Snakeroot. The most famous of these unfortunate people was Abraham Lincoln’s mother, Nancy Hanks Lincoln.

White Snakeroot (Agertina altissima) gone to seed.
White Snakeroot (Agertina altissima) gone to seed.

White Snakeroot  is a herbaceous perennial that gets its name from the root decoction made by American Indians as a cure for snakebite. The Cherokees have used it as an anti-diarrheal, kidney stone and urinary disease medicine.

The current scientific name is Agertina altissima, the old name was Eupatorium rugosum. White Snakeroot was also called, ‘Tall Boneset’. It is considered a member of the aster family.

It was called “Boneset’ because it was used to treat breakbone fever, a term describing the high fever that often accompanies influenza.

I tried pressing this plant in my big plant press and had some trouble. When I checked the plant after pressing it, the page with the plant had about fifty dead gnats on the page (sorry, gnats). Apparently, the late flying gnats use this plant, whether for food or shelter I don’t know.

So, I am trying to press the plant again but am trying to shake out the insects first.

White Snakeroot is also sold as a garden plant, Ageratina altissima ‘Chocolate’. This variety has dark-tinted foliage and white flowers which makes a striking addition to the garden. Just don’t eat it.

White Snakeroot (Agertina altissima) in bloom until frost.
White Snakeroot (Agertina altissima) in bloom until frost.

White Snakeroot (Agertina Altissima)

Flowers: white flowers from September to frost

Range: eastern North America and Canadian Northwest territories

Height: 3 to 5 feet, spreads to 2 to 4 feet

Light: partial shade to shade

Soil: rich and moist

Growth habit: spreads by rhizomes and self-seeding

Propagation: divide vigorous clumps, seed germination is low

Attracts: birds, butterflies, insects and other pollinators

Need more garden flower ideas? Check out Long blooming plants: A plant list.

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