Staff at Midwestern Consulting recently proposed plantings for a green roof and courtyard project. The plants included something unfamiliar, White Snakeroot (eupatorium rugosum). So we looked it up.
The plant is pretty but toxic. It causes “milk sickness” in people who drink milk from animals that eat it. White Snakeroot killed thousands of people, including Nancy Hanks the mother of Abraham Lincoln, in 1818 at the age of 34. Abe was nine at the time.
While it isn’t likely that cows or goats will be grazing on the roof or in the courtyard of this particular project, a lesson was learned. It is important to check proposed plantings for toxicity for particular uses and locations.
The fact is that many ornamental plants, or parts of plants (leaves, berries, bulbs, roots), are toxic to some extent and during different stages of their growth.
Most home gardens contain at least some toxic plants. Some of the most popular ornamentals are toxic including shrubs like Rhododendrons and Hydrangeas, trees like Horse-chestnut and Holly, house plants such as Dieffenbachia and Croton and other perennials and annuals.
So are some of the things we grow in the garden. Ingesting rhubarb leaves can be fatal. A few Daphne berries can kill a child. A couple of castor beans can kill an adult (the toxin “ricin” is derived from castor beans). And eating the foliage on the common yew can be fatal.
And to make things a bit more confusing, some plants are safe to eat at some times and potentially fatal at others.
Poke salad is featured in “Poke Salad Annie” or “Polk Salad Annie“, a 1969 song written and performed by Tony Joe White. Its lyrics describe the lifestyle of a Southern girl. Make sure you know what you are picking. Poke, phytolacca/pokeweed, is toxic when it gets over a foot or so high.
So plant selection and an awareness of plant toxicity are important!
For more complete plant toxicity information, please go here: http://aggie-horticulture.tamu.edu/lawn_garden/toxicson/toxicson.html
Earl Ophoff is a senior project manager and registered landscape architect at Midwestern Consulting in Ann Arbor, Michigan. Contact Earl at firstname.lastname@example.org.