Cindy, it is my experience that most herbs are both huge and invasive. I just keep a tight rein on them and only allow them where they have a designated spot. Some are worse than others - lemon balm and vervain are particularly eager to join everyone's party. Some I let grow sparingly wherever they land - feverfew for a white pop here and there, borage for the bees but I only allow one every 10 feet in any direction, and sweet annie for her lovely fragrance. I also let calendula naturalize amongst all the beds, but again I pull the majority of them. Still a work in progress, and this year I had some outside issues that needed attending to and the herb garden is in a bit of disarray -- but will recover for next season. You really can't kill any of these thugs.
