Bart from Fernandina Beach writes
Hi-Yield Atrazine Weed Killer is not labeled to control Bermuda grass in St. Augustine. Unfortunately, because Bermuda and St. Augustine grasses are so closely related, there is nothing that will kill the Bermuda without harming the St. Augustine as well. It is typically recommended to spot treat the Bermuda with a non-selective glyhposate product and kill it directly, and then replant St. Augustine in those areas if necessary.
Answer last updated on: 05/09/2018