Although lemon balm (Melissa officinalis) can be quite invasive, if it takes over your garden, do not bamlem the cats.
They all swarmed to me last night, all the wild ones I feed, they always come and flock around me when they hear my footsteps coming home from work in the night. They take turns to run in front of me, stop and look into me and do the blink and I say to each one, hello baby and then they run behind me and another one comes. This is how we go home, down the lane in the moonlight. And then I fill their drinking waters and make a long line of cat beads on the big flat stone and they line up in their hierarchy and eat together, from queen to kitten and the toms usually eat after, alone, and I go to bed.