BY DR. AMANDA GREV, Extension Specialist, Pasture and Forage, Western Maryland Research and Education Center
– originally published in the June 2025 issue of The Equiery –
Tired of looking at your pastures and seeing that sea of yellow every summer?
Although the distinctive yellow flowers don’t typically appear until late spring or early summer, buttercup is actually a cool-season plant that grows during the cooler fall, winter, and early spring months. There are a number of different species of buttercup that are common in our area, including bulbous buttercup (Ranunculus bulbosus), tall buttercup (Ranunculus acris), hairy buttercup (Ranunculus sardous), and small flower buttercup (Ranunculus arbortivus).
Buttercup can be toxic to horses. The toxin protoanemonin is present in all parts of the plant and is released when the plant is chewed, crushed, or damaged. Animals that eat buttercup may suffer blistering in the mouth and internal parts of the gastrointestinal tract, diarrhea, colic, and in severe (very rare) cases, death. Fortunately, buttercup’s acrid taste usually deters grazing animals. Clinical signs are typically seen only in animals forced to consume buttercups because they have nothing else to eat.
By the time the showy yellow flowers appear, however, we have likely missed the optimum window for controlling buttercup. Buttercup is opportunistic and flourishes in thin or overgrazed pastures. The best way to control buttercup is by outcompeting it with a healthy, vigorous, and desirable forages. Prevent overgrazing and maintain good vegetative cover to prevent it from spreading, especially during the fall and winter months. Allowing pastures to rest by implementing rotational grazing and not grazing pastures too short can also help.
Mowing pastures in the spring before buttercups produce flowers may help reduce the amount of seed produced, but mowing alone is not enough to eradicate buttercup from pastures. In fact, continued mowing to get rid of the buttercup flowers may also inadvertently harm desirable pasture grasses if the mowing is too frequent or the grass is cut too short.
Buttercup can tolerate a more acidic, nutrient-poor soil compared to many of our desired forage species. This means that bringing pasture soils up to an optimum pH and fertility level can help desirable forage thrive and outcompete buttercup. The optimum soil pH is somewhere between 6.0 and 7.0 for most for ages. A soil test will tell you the pH and fertility status of your soil. If you need help with soil sampling or interpreting a soil test report, call your local county Extension office, and they can help walk you through the process.
Lastly, there are several herbicides available for chemical control of buttercup. The plant growth regulator herbicides, including products containing 2,4-D and dicamba, are effective against buttercup, as is Crossbow, which is a mix of 2,4-D and triclopyr. Herbicides will be most effective if applied before the buttercups bloom, which means the best time to spray is either in late fall when plants are just germinating or in the early spring before flowers are visible. Once buttercup has flowered, herbicides can offer some control, but you will likely need to reapply the following year for more effective coverage. Keep in mind that these products can kill or injure desirable broadleaf forages such as clover as well. Be sure to follow all guidelines on the product label prior before using any herbicide.
Buttercup is both visually distinctive and troublesome. The most effective control of buttercups requires a multi-faceted approach that includes a combination of good grazing management to maintain a healthy forage stand, proper liming and fertilization following soil test guidelines, and in some cases, an appropriate herbicide applied at the correct time.
