For some people Bermuda grass is a desirable lawn grass, but for others it is an invasive weed. If you fall into the latter category and you wish to kill Bermuda grass without hurting your flowers, take heart. While Bermuda is difficult to kill and control, it is possible for you to remove it from your garden without harming the vast majority of your flowers. It isn't easy, however. Bermuda grass spreads by seeds as well as by above-ground shoots that take on new roots and begin sending out shoots of their own, and by underground rhizomes, or roots, that can spread several yards before suddenly sending new grass to the surface. Killing Bermuda in a flower bed, without harming flowers, can be a long process--but the battle can be won.
Water your garden well, including the Bermuda grass. Wait two days after watering.
Spray your Bermuda grass with a Bermuda-grass-specific herbicide. Talk to your nurseryman or with a knowledgeable person at your home improvement center about a Bermuda-specific herbicide that is safe for the majority of flowers in your garden. Spray on a day with little wind and do not spray if rain is forecast within the next 24 hours. Do not water for at least 24 hours after spraying, and wait seven days for the Bermuda grass to die.
Remove as much of the dead Bermuda as possible with a trowel and rake. Wear gloves and pull as many of the roots as you can after loosening the soil with your trowel.
Water the garden and watch for new Bermuda growth. Within three days of seeing new Bermuda growth, spray it with the Bermuda-specific herbicide. Again, spray on a day with little wind and do not spray if rain is expected within 24 hours. Do not water for at least 24 hours after spraying.
Remove the dead Bermuda grass seven days after the second spraying.