White snakeroot - A toxic plant of Iowa

September 12, 2016 12:48 PM
Blog Post

As you venture around the countryside this time of year you might notice the presence of a plant with white flowers along the edge of woodlands. There is a good chance this plant is white snakeroot, a perennial in the Asteraceae (sunflower family). The plant is adapted to shady areas with low levels of disturbance, and typically reaches heights of 2 to 3 ft.



White snakeroot is typically found on the edges of woodlands.

While rarely given a second thought now, at the time when the Midwest was being settled by European settlers white snakeroot was responsible for the deaths of many thousands of  settlers. The plant contains a toxin that was responsible for what was known as ‘milk silkness’. The settlers would let their dairy cows graze in woodlands where they would encounter white snakeroot. The cows rarely would consume a toxic dose, but the toxin accumulated in the milk and caused the mysterious ailment milk sickness. The settlers were unable to determine the source of the toxin for several decades. Milk sickness was responsible for the death of Abraham Lincoln’s mother when he was 9 years old.  



The white flowers are present in early fall in Iowa.

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Bob Hartzler Professor of Agronomy

Dr. Bob Hartzler is a professor of agronomy and an extension weed specialist. He conducts research on weed biology and how it impacts the efficacy of weed management programs in corn and soybean. Dr. Hartzler also teaches undergraduate classes in weed science and weed identificatio...