Eradicating Poke Seed Plants
Most of the broad leaf weed treatments listed at the link below should work great. (the 2 and 3 way products will work best). Particularly effective are the products that contain the active ingredient "triclopyr". Please note that it is generally not advisable to spray for weeds when conditions are dry and hot. If treatments are applied in these conditions the lawn could be damaged and weeds will not respond well to treatments. It is always best to spray systemics when weeds are actively growing and there is enough soil moisture to provide uptake of the product that is applied. Thanks.
See link for more information: http://www2.ca.uky.edu/agc/pubs/agr/agr78/agr78.pdf