I can think of only four plants at our place that are poisonous for livestock. They are sneezeweed, cowbane, prairie dogbane and horse nettle. That’s not bad for the 135 wildflowers we’ve identified on our property.
Sneezeweed
Sneezeweed, also called bitterweed or bitter sneezeweed, grows to 2 feet tall and has bright yellow flowers. It is found in waste areas and overgrazed pastures. Plants bloom August – October. It is poisonous to livestock, so cattle and horses avoid it. If honeybees collect nectar from the flowers, the honey is so bitter it can’t be used. The milk of cattle that graze on it is bitter. That’s why it’s called bitterweed.
It’s called sneezeweed because pioneers used the dried seedheads to make snuff. Native Americans used the dried flowers as snuff for head colds and drank a tea for intestinal parasites.
Cowbane
Cowbane is in the parsley family and looks like miniature Queen Anne’s lace. It’s called cowbane because it is poisonous to cattle and other livestock. A cow that ingests it could die within 15 minutes. It is one of the most toxic plants in North America. It grows to several feet tall and is common around ponds, marshes and wet prairies. In the past, a homeopathic remedy was made from the plant and used to treat epilepsy, meningitis and other ailments affecting the brain.
In fiction, an infusion of cowbane was prepared during Harry Potter’s “Potions” class at the Hogwarts School of Witchcraft and Wizardry. It was an ingredient in the recipe for making the Shrinking Solution. Cowbane blooms from mid to late summer.
Prairie dogbane
It was only recently that I identified prairie dogbane. It grows throughout North America and is most abundant on sandy or gravelly soils. Plants grow to 4 feet tall. All parts of the plant are poisonous and if eaten can cause cardiac arrest. It is poisonous to humans, dogs, cats and livestock. Probably any mammal, I suspect.
It has white flowers, red stems and a white sap, which is seen if the leaves are cut or broken. I thought it was a milkweed at first. I’m not sure why it’s called dogbane because I doubt any dog would ever eat it. Livestock might, but since there’s already a cowbane, I guess they had to come up with a different name. Probably not horsebane either since there’s a horse nettle. The plant flowers May – August.
Prairie dogbane is also called Indian hemp, because Native Americans used the fibers for rope and nets. They also used the plant to treat a variety of ailments, making laxatives, respiratory aids, cough medicines and a tea to treat intestinal parasites.
Horse nettle
Horse nettle belongs to the nightshade family. It is common in weedy pastures, fields and waste areas. Plants grow to 3 feet tall and have spiney stems and leaves and white to pale violet flowers. The plants flower May – September. After flowering, yellow berries are produced. They are ½–¾ inch in diameter. The berries are poisonous to humans and livestock.
However, upland game birds eat the berries. Berries were once used to treat epilepsy. Native Americans gargled leaf tea for sore throats and drank the tea for intestinal parasites. Poulticed leaves were used to treat poison ivy.
