Pastures this spring popped with a bright yellow flower. While it creates a picturesque landscape, this particular flower is a weed, and it is poisonous to livestock.
Buttercup came out in force in Missouri this spring. It flowers from March through August, says Sarah Kenyon, University of Missouri Extension agronomist, and every part of this plant is poisonous to livestock.
Buttercup has a toxin known as protoanemonin that is released when the plant is chewed.
“It causes blistering in the mouth of the animal and can cause damage throughout the digestive tract,” Kenyon explains. Grazing it in large quantities causes convulsions and death.
The animals react to the plant when they consume it, and Kenyon says they feel the effect immediately. “They instantly get the soreness in their mouth and throat,” she says, “so they do try to avoid it."
There are many species of buttercup, but the most common in Missouri is the bulbous buttercup. The name, according to the University of Maryland Extension, reflects the plant’s bulb-like base, called a corm, just below the surface. This corm stores energy, improving the plants survivability during hot, dry summers and winter.
Once it emerges, buttercup remains close to the ground. In early spring, it bolts, producing a five-petal flower with crowfoot-shaped green leaves divided into three sections. When present in a pasture, Kenyon says, farmers should avoid grazing livestock.
John D. Byrd, Mississippi State University, Bugwood.org
NO LIVESTOCK ALLOWED: All parts of the buttercup plant are toxic to livestock. Grazing is not recommended. However, it can be baled for hay, as its dry form is less toxic.
It can be difficult to control buttercup because it is a perennial, meaning it comes back year after year.
“You can mow it to reduce seed production,” Kenyon says, “but that becomes tricky because it will go ahead and produce a flower below the cut line.” She recommends a herbicide for control.
Prepackaged herbicide mixtures containing 2,4-D or 2,4-D with dicamba, such as Banvel and Clarity, are effective at controlling buttercup. The University of Maryland recommendations call for 1 pound of active ingredient per acre.
Kenyon says the timing of herbicide applications is important. Once farmers see the yellow flower in the spring, it often is too late. Pay attention this year to those fields with buttercup and plan for a fall or an early-spring herbicide treatment, she adds. The optimum time for spring is when temperatures are at least 60 degrees F.
Buttercup thrives in overgrazed pastures or thin stands. One additional control measure is to make sure there is a good stand of grass that can outcompete this weed in the field.
Buttercup in hay
With adequate growth, some pastures are harvested for hay.
If buttercup contaminates the hay, Kenyon says farmers do not need to be as concerned. The toxin volatilizes out of the hay, making it inactive. When dried, it is safe to feed animals.
While buttercup may be pretty to look at, farmers need to be diligent to protect their animals from this poisonous plant.