How do I kill yellow wood sorrel in my lawn?

• Yellow wood sorrel is also known as Oxalis stricta. It can be removed from the lawn using a selective herbicide that does not harm the existing lawn but controls broadleaf weeds. This is best applied in spring or autumn when weeds are actively growing and not stressed.
• Spot spray with a glyphosate based herbicide that kills down to the roots, this will also kill any surrounding grass so only spray the weeds you want to control.  
• Alternatively, remove the weeds by hand using a knife, making sure the root is removed so that it does not re-emerge.
• Once the sorrel has died down rake out the dead patches and resow the area with seed that matches the existing lawn.