The appearance of yellow buttercup flowers in pastures and hay fields is a sign that spring has arrived, but they are toxic to all livestock species.
The toxin, protanemonin, is present in all parts of the plant and is released when it is chewed or otherwise wounded. Animals that eat buttercups may suffer from blistering of the mouth and internal parts of the gastrointestinal tract, diarrhea, colic, and, in severe cases, death.
Fortunately, most animals won’t eat buttercup because it they’re unpalatable. The toxin becomes inactivated when dried so buttercup is not a concern in hay.
Vegetative growth of buttercups occurs in winter months. As a cool season weed, this plant often flourishes in over-grazed pastures with poor stands of desirable forages. In fact, many fields that have dense buttercup populations are heavily grazed by animals during the fall through early spring months. Buttercups are sometimes classified as short-lived perennials, but often grow as winter annuals.
Most buttercup plants emerge from seed during the fall or late winter months. Therefore, pasture management practices that improve and promote growth of desirable plants during these months is one of the best methods to help compete against the emergence and growth of this plant.
Mowing fields or clipping plants close to the ground in the early spring before buttercup plants can produce flowers may help reduce the amount of new seed produced, but mowing alone will not totally eliminate seed production.
For chemical control, herbicides registered for use on grass pastures that contain 2,4-D will effectively control buttercup. Depending on other weeds present, products that contain dicamba+2,4-D (eg. Weedmaster), aminopyralid (eg. ForeFront, Milestone), triclopyr (eg. PastureGard, Crossbow), or metsulfuron (eg. Cimarron) can also be used.
However, legumes such as clovers inter-seeded with grass pastures can be severely injured or killed by these herbicide products. For optimum results, apply herbicide in the early spring (February to April) before flowers are observed, when buttercup plants are still small and actively growing.
For best herbicide activity, wait until daytime air temperatures are greater than 50 degrees for two to three consecutive days. To determine which product is best for your operation, be sure to read product labels to find out the details about grazing and haying restrictions as they vary widely between these products
An effective weed control program is essential to establishing and maintaining highly productive pastures and animal performance. We need to remember the idiom, “An ounce of prevention is worth a pound of cure.” Select well-adapted grass and/or legume species that will grow and establish rapidly. This will minimize the length of time for weeds to invade easily. Lime and fertilize according to soil test recommendations.
Proper pH and nutrient status will help insure that the forage will grow rapidly and be more competitive with weeds. Manage grazing properly. Overgrazing is a common cause of weed problems. Heavy grazing pressure may favor weed growth over grass.
Identify weed problems and location and select which option or combination of options you plan to use for weed control (mechanical, chemical, or grazing management), but the most important is to put it in practice and evaluate the outcome.