Well yes, that's obviously the only irrigated patch in a parched wasteland and that's why the grass is there, but one assumes NaturallyGreen is trying to nurture that valiant oleander.
I didn't mean to imply you suggested plastic, just saying I've never seen any mulch eradicate Bermuda grass roots. In my experience, BG is like cockroaches, you might temporarily knock it back in one place but the runners just pop up elsewhere. Happy to hear you've been more successful.
That patch is so small it's still diggable—soak well the day before and just dig out every visible stolen. Then, as Stone suggested, lay a wide perimeter of organic matter around the oleander...for the oleander's sake and to reduce watering needs.
