Home / Blogs / White Snakeroot, a Pollinator-Pleasing Plant with a Nefarious Past
October 27, 2021
White snakeroot blooms on Oct. 19, 2021. The bushy, shrub-like native perennial provides pollinators a food source at a time when many other garden blooms have long since withered. (Photo by Will Parson/Chesapeake Bay Program)
Like cats and dogs or Hatfields and McCoys, humans and white snakeroot (Ageratina altissima) haven’t always gotten along.
Indigenous People knew the plant’s roots and foliage to be poisonous, and while they used it for medicinal purposes, would not eat it. When European colonists arrived and started domesticating animals, they learned the hard way that if cattle ended up eating white snakeroot, their milk would turn poisonous. People who drank this milk found themselves with a bad case of “milk sickness,” an illness that causes flu-like symptoms and even death.
Toxicity from consuming contaminated milk was a big problem in colonial times when many families had backyard farms. Nancy Hanks Lincoln, Abraham Lincoln’s mom, allegedly passed away due to milk sickness in the fall of 1818.
Though harmful in the past, white snakeroot is far less dangerous thanks to improved farming techniques and a modernized dairy industry. The shade-loving perennial flourishes in forests but can also be a nice touch to a home garden. It can grow up to four feet tall and boasts dark-green leaves and pretty white petals that start blooming in summer and continue right up until winter frost.
White snakeroot’s greatest appeal is what it provides insects. Because the plant blooms so late in the season, its flowers provide much-needed food to bees, moths and flies searching for sustenance during the autumn. Flies will also lay their eggs on white snakeroot leaves for them to hatch in the spring. By using your plants to provide insects with food and shelter, you can help slow down their rapid decline. Having a greater number of insects around also means more food for our birds, which are also in trouble.
Besides its toxicity, white snakeroot’s only drawback is that it can easily take over parts of your garden. The plant will inconspicuously grow in shady spots all spring and summer and then dominate the yard come fall. It produces a high amount of seeds that can spread across your entire garden on a windy day. Its fast-growing rhizomes (roots that grow horizontally) also cause the plant to flourish.
We at the Alliance love white snakeroot; it’s one of a limited number of native wildflowers that flourishes in the shade of the forests that we cherish. We also recommend the plant in our landscape projects due to the food it provides insects. It’s even a part of the native plant garden at our Annapolis, Maryland office where it helps feed pollinators and reduce stormwater runoff.
Now that we know how to avoid white snakeroot’s toxicity, we can use the plant to spice up our gardens or forests with pretty white flowers, food for wildlife, and just the right amount of danger.
Web Content Manager, Chesapeake Bay Program
Forests for the Bay