Originally Posted by CWS4322
I use 3# coffee cans, end cut off or chimney bricks as planters for the invasive herbs. I bury the coffee can, leaving about 1 inch above the ground and plant the plants in those. So far, they haven't "climbed" out of their cans and invaded other areas. Ditto for the chimney bricks. I know of people who've used old tires for the same purpose.
Ah - but those methods only work with plants that are invasive via their root systems - like mint, tansy, etc. Perilla/Shiso is invasive via its prodigious self-seeding (anise hyssop & lemon balm are invasive the same way), thus the only way to keep it in control is to either cut off the blooms before they set seed, &/or be extremely diligent in weeding out volunteer plants when they appear.