As the signs of spring appear, calls and questions regarding forage weed control are on the rise. In untreated pastures and hayfields, there are likely dozens of cool season broadleaf and grass weed species that blanket the landscape. One of the most high-profile broadleaf weeds in this mix is buttercup (Ranunculus spp.), a species that turns fields into a sea of yellow blooms by mid- to late-spring.
There are roughly a dozen species of buttercup across the Southeast. Most of these species are either biennial or perennial, meaning they will return the following year from both seed and tuberous roots. The most common species found in Alabama are hairy buttercup, bristly buttercup, and littleleaf buttercup. While some buttercup species were introduced to the Southeast, many buttercups are native to Alabama and are well adapted to the environment. They begin to emerge in the fall as warm season forage growth and soil temperatures decrease. Generally, buttercup prefers moist sites and easily grows in areas where forages are thin.
All buttercups of the Ranunculus genus contain a toxic compound called ranunculin. This compound produces an oily substance when the plant parts are crushed or eaten by grazing livestock. If consumed, these compounds can cause blisters in the animal’s mouth or nosebleeds in cattle. Because of its bitter taste and toxic properties, cattle usually avoid consuming buttercup. However, large stands of buttercup may be difficult for livestock to avoid when the fields are covered each spring.
If producers begin to see a flush of green vegetation across their fields this spring, buttercup is likely in the mix. By controlling buttercup, as well as other winter broadleaf weeds, desirable forages are more likely to receive the full benefit of any fertilizer applications. Mechanical control such as disking or mowing does little to control buttercup. Therefore, the most effective options are timely herbicide applications when plants are small and actively growing. These timely herbicide applications should result in increased forage quality, yield, and overall better grazing opportunities for livestock.
Recent field demonstrations in north Alabama were conducted to evaluate treatments of 2,4-D Ester, GrazonNext HL, and Weedmaster. These treatments were applied in November, December, and March to determine their effectiveness in controlling buttercup. By May, six months after the initial November application, all treatments at each application date resulted in more than 75 percent buttercup control. GrazonNext HL at 1 pint per acre and 2,4-D Ester at 10.8 fluid ounces per acre each had at least 95 percent control at each application date. These results suggest that producers can use lower product rates on younger weeds while field conditions are still good enough to accommodate equipment, as opposed to waiting until late spring when pastures are often waterlogged from frequent rains.
Although control of buttercup during fall and winter is preferred, there are also viable control options for buttercup during the spring. Even though blooms may appear, products like GrazonNext, Duracor, and 2,4-D are still effective when applied prior to weed maturity. For producers using 2,4-D alone, it is recommended to increase rates to at least 1.5 pints per acre because of the increased plant size and maturity. Producers can expect activity on other broadleaf weeds like chickweed, henbit, dandelion, marestail, curly dock, and plantain, which should also be growing alongside buttercup. Each of these are relatively inexpensive treatment options. This rate of GrazonNext HL is approximately a $7 to $9 per acre treatment, whereas 2,4-D Ester (Shredder LV6 – 5.6 lbs 2,4-D acid/gal) and Weedmaster may be as low as $5 to $7 per acre.
If producers are concerned about saving perennial clover but still want to control buttercup, an earlier application (November, December, or March) of 2,4-D or Pursuit is recommended instead of GrazonNext HL or Weedmaster. In these field trials, established white clover was suppressed for 2-4 weeks from 2,4-D Ester but returned to normal growth by the spring.
When using any herbicide product, whether for buttercup or other weeds, please remember to carefully read and follow all herbicide label recommendations.
Take Home Points
- Buttercups of the Ranunculus genus contain compounds that are toxic to grazing livestock.
- Broadcast applications of GrazonNext, Duracor, Pursuit, or 2,4-D can be effective in buttercup control.
- Established perennial white clover has high tolerance of Pursuit or 2,4-D applications.
Trade and brand names used in this publication are given for information purposes only. No guarantee, endorsement, or discrimination among comparable products is intended or implied by the Alabama Cooperative Extension System.