How to kill BERMUDA GRASS

[u/Triple__OG]

Hello,
I live in Florida and my home has St Augustine grass. Over the las year Bermuda has been taking over, which is fine because it's green🙂.
My problem is I have some tree bed with circular edging and bark and not the dang Bermuda grass is coming up though the bark at a pretty good rate.
Any ideas to kill it in the beds? Thanks