Both Dicamba and MCPA are active ingredients found in many products, however many of these may cause damage to St. Augustine grass. A good choice that contains both would be Monterey Spurge Power, which can be used as spot treatment on St. Augustine lawns since it may cause some discoloration. Be sure to read and follow the product label to be sure that it will suit your needs. Another option is Speedzone Southern Herbicide, which also contains two additional active ingredients and is a formula that may be more gentle on your turf, or Trimec Southern Broadleaf Hervbicide. Be sure that your target weeds are on the product label of the herbicide that you choose to apply.
It can take up to 2 weeks after application of Spurge Power to start to see results.
Spurge Power is labeled to control ground ivy also known as creeping charlie. Per the Product Label: Apply SPURGE POWER® at the rate of 1.0 to 1.25 fl. oz. in 2 gallons to 5 gallons of water per 1,000 sq. ft. to control weeds growing in lawn planted to Bluegrass, Fescue, Rye, Bent (excluding golf greens and tees), Bahia, Bermuda, and Zoysia.