Lemon Balm is astoundingly resilient. Once ONE of those buggers flowers that soil will forever harbor lemon balm seeds. I feed it to the rabbits. The gravely area on the side of the house that's still covered with rocky fill from rebuilding the porch is being taken over by lemon balm instead of grass. This works nicely for me, as it's lower maintenance. While it CAN be mowed, if you normally use one of the higher cutting settings on your lawnmower, you won't notice the difference. I'm tempted to replant the yard with lemon balm when my wife and I finally do something about it.