Cf from Fl writes
Monterey Grass Getter Herbicide is a grass killer, so it will injure the St Augustine and should not be used on lawns. Unfortunately, Bermuda grass is so closely related to St. Augustine grass that there is nothing that will remove Bermuda from St. Augustine and not hurt the Bermuda as well. In your situation it is recommended to spot treat the Bermuda with Round Up and kill it directly, and then replant St. Augustine in those areas. We do carry some professional round up products.
Answer last updated on: 06/11/2017