Broadleaf herbicides can be applied over grassy areas infested with creeping buttercup to selectively kill the buttercup and not the grass. Products containing the active ingredient
What weedkiller kills buttercups?
Kill it With a Spot Spray Weedkiller for Lawns
I'd recommend using Scotts Weedol Lawn Weedkiller Spot Spray or Resolva Weedol Lawn Weed Killer. Give it a blast, you might need to do it again after 6 weeks if the plant is strong.
What do you spray buttercups with?
“Broad-spectrum herbicides such as Pastor on silage ground and Forefront T on land grazed by cattle and sheep, are good options for early applications to catch both buttercups and dandelions.” Ragwort will be the next weed to start growing, followed by docks and thistles.