By: Steve Roark
Volunteer Interpreter, Cumberland Gap National Historical Park

You have no doubt noted the large swaths of yellow flowers in pasture and hayfields this Spring. Those are buttercups, and while picturesque, are not welcome to farmers because they can poison cattle and take up growing space that should be growing grass.

Buttercups are easy to identify by their waxy bright 5-petaled flowers and deeply cut leaves. The flowers glow brighter than other flowers because of layers of air trapped just beneath the surface of the petals that act like reflecting mirrors increasing their bright appearance. This is beneficial to buttercups as the brightness can be seen by insects to help them home in on the flower for pollination.

Buttercups are classified as poisonous due to a compound called ranunculin, which breaks down when ingested or crushed to form a toxic oil that causes dermatitis and even blisters on the skin and blisters on the lips and mouth if ingested. All these negatives are true for cattle as well as humans, and because of this and their acrid taste, cattle will not eat them unless the pasture is poor and they are desperate. Consuming hay with buttercup mixed in is not toxic because the oil breaks down when it dries. However, buttercup is still detrimental to hay production because they are competing with the grass for sun and nutrients. There are 12 species of buttercups that grow in our area, and most are native. But the ones you most often see in fields and causing problems are invasive aliens: Hairy Buttercup and Bulbous Buttercup. Spraying a broadleaf herbicide is about the only solution to eliminate buttercup from farm fields, and the recommendation is to spray late summer or early spring. Contact your local Ag Extension Service for advice.

Despite their toxicity, buttercups have a long history of medicinal use, including treating rheumatism, arthritis, cuts, bruises, even hemorrhoids. Needless to say, medicinal use of the plant is not recommended.