White Snakeroot

White snakeroot (Ageratina altissimo, formerly Eupatorium rugosum) is a native plant that good for bees.  It is not so good for humans, we are told Abraham Lincoln's mother, Nancy Hanks Lincoln, died of milk sickness, which is caused by drinking the milk of cows that have eaten white snakeroot.

She was thirty-four and he was nine. History tells us that milk sickness was not eliminated until the 1920s, because what do natives and women know?

Eventually, a frontier doctor in Illinois named Anna Pierce Hobbs Bixby learned of the cause of the sickness from a Shawnee medicine woman. Bixby helped control the disease locally by instructing settlers to remove white snakeroot from their fields, but she too was largely ignored by the medical community, and research confirming the connection between snakeroot and milk was only published much later. Today, for better or worse, industrial agriculture has all but eradicated milk sickness.

My puzzle is that various sources have different takes on how much sunlight white snakeroot needs. The plant is said to be easy to grow from seeds, so I'll try for myself.

https://wildseedproject.net/2016/03/in-the-shade-gardening-with-native-plants-from-the-woodland-understory/ Recommends White Snake Root Ageratina altissimo for deep shade.

Donald J. Leopold, Native Plants of the Northeast: A Guide for Gardening & Conservation, Tenth Printing, 2020, Timber Press, Inc.; ISBN-13: 978-0-88192-673-6 (Eupatorium rugosum) says - sun to partial shade. 

https://www.wildflower.org/plants/result.php?id_plant=agal5 says Ageratina altissima used to be placed in the genus Eupatorium and says - prefers full sun. 

https://www.mortonarb.org/trees-plants/tree-plant-descriptions/white-snakeroot says "best in part shade to full shade". 

https://www.toadshade.com/Ageratina-altissima.html says "its native habit is often woodland or woods-edge."