Driving down the road you may enjoy seeing pasture and hay fields full of lovely yellow flowers, which are buttercups. While I agree they create an attractive scene, they are a wolf in sheep’s clothing in that they are toxic if eaten by livestock and compete with the grass for nutrients, sun and other resources.

Buttercups are easy to identify with their cup shaped, 5-petaled flowers that are lustrous because of a layer of reflective cells that make them look shiny. Their bloom period is mid-April to May, but some may bloom on into summer. There are many species of buttercup worldwide, but the two most often seen in fields are hairy and bulbous buttercup. They started out along roadsides but their propensity to produce heavy seed crops have allowed them to spread into grass fields and they are particularly widespread this year.

Healthy well managed grass is lush enough that it can generally fend off buttercup infestations by keeping the ground well shaded. But overgrazing and under fertilizing fields can create thin areas where buttercups can get a toe hold and begin to spread. Farmers must often resort to using a broad leaf herbicide to eradicate the weed.

Cows and other livestock are pretty savvy when it comes to eating and will avoid eating buttercup because it has a bitter taste, and If you look close you will note that cows graze heavily on grass right up to it but not eat it. However, if grass is in short supply from drought or overgrazing, livestock may resort to consuming the plant. If they eat a high enough dose, livestock will shortly show digestive distress and drool heavily, and may also have diarrhea and bloody urine. Horses seem to be particularly sensitive to buttercup toxicity.

Some folklore about buttercups include a belief that the rich yellow color of butter originates from cows eating buttercups. And there was a children’s game where a buttercup is held under your chin, and if it reflects a yellow color, then you are fond of butter (I heard this for dandelion as well). While buttercup is also toxic to humans, there is some folk medicine lore purporting it as a treatment for rheumatism.

By Steve Roark
Volunteer Interpreter for Cumberland Gap National Historical Park