The best thing about Zamzows Ultra weed killer is that it works at temperatures of 45 degrees to 85 degrees. Other weed killers don't start to work until it is 70 degrees. Just using Ultra Weed Control spray is not enough to get the clover.
You must also add Stay put with the spray. Stay put is a surfactant that helps the weed control spray stick to the waxy surface of the clover and helps it adhere the herbicide onto the leaves even if they get wet from watering. Stay put boosts the killing capacity of the Ultra by 30%. Use the Ultra Weed Control spray, with the Stay put additive, and spray the clover every 7 days, and you will soon eliminate your clover.