If its weeds & not Chicory - then Mow it. Mowing is the Best way to reduce annual weed growth. Get it before it seeds -and Next year it'll be sweet.

If you even need it - Don't fertilize it until Fall or Spring. Applying fertilizer over the top in the summer will probably help annual weeds more than the clover. Clover (if its inoculated) makes its own Nitrogen and doesn't need any additional.

FH