By: Neil Rhodes, Professor and Extension Weed Management Specialist, University of Tennessee Extension
Tired of looking out across your pastures and hay fields and seeing that "sea of yellow" every spring? Unfortunately, many producers in Tennessee are all too familiar with buttercups. Most of these members of the genus Ranunculus are winter annuals that are easily controlled with a timely application of 2,4-D.
Historically, most applications for control of buttercups have been in late winter to early spring. As we have discussed numerous times, one of the most important keys to getting good results is to spray buttercups before they bloom. While every year is different weather-wise, March is usually the best time for late winter sprays. Buttercups are actively growing then and usually have not begun to bloom. Another reason for spraying at this time is that musk thistle can be controlled at the same time.
In most cases, 2,4-D ester at 1 qt/ provides excellent control of annual buttercups and musk thistle. Favorable weather (3 days of day time highs of 60 F); plenty of water (at least 20 gallons per acre spray volume); and the addition of a good, nonionic surfactant (1 qt/100 gallons of spray mix) are all important ingredients in success. If possible, avoid spraying right before a cold front is predicted when temperatures are expected to drop substantially. Also, if buckhorn plantain is also troublesome in the same fields, consider increasing the rate of 2,4-D. A benefit to using 2,4-D for buttercup, thistle and buckhorn plantain control rather than some of the newer pasture herbicides is that 2,4-D breaks down quickly in soil, and therefore clovers can be planted the following year without carryover concerns.
As with all herbicide applications, producers are encouraged to practice good stewardship. Avoid spraying on windy days, and if at all possible, apply 2,4-D and other pasture herbicides with a dedicated pasture sprayer, and not one that you plan to use to spray cotton, soybeans and other sensitive crops. Also, sure to thoroughly read the herbicide label, and adhere to all precautions prior to applications.