Borax has been used as an herbicide since the 1920s. Boron, its active ingredient, is lethal to broad-leaf weeds like creeping charlie plants in very small amounts. And since the lethal dosage for broad-leaf weeds is less than the lethal dosage for lawn grass, Borax can be safely used to kill creeping charlie growing in your lawn. However, your lawn can only tolerate so much. Boron accumulates in the soil and repeated use can form hot spots that may create brown spots in your grass. Borax can only be used once annually for two years before dangerous levels are accumulated. If creeping charlie persists, switch to an herbicide prescribed for use on the plant.
Add 10 ounces of Borax in 1/2 cup of warm water. Mix well until all the Borax is dissolved.
Add the Borax solution to 2.5 gallons of water. Mix well.
Add this mixture to your hose-end sprayer.
Cover any desirable broad-leaf plants on the edge of your lawn with plastic to avoid accidentally spraying them.
Spray the lawn, following your hose-end sprayer's instructions for application rates, so that it is coated evenly with the solution. The above formula is enough to cover 1,000 square feet of lawn. For the best results, treat creeping charlie in the spring when it is actively growing. Spray early in the morning on a day with no wind and no rain forecast for the next 48 hours.