When THOSE plants get tired and need dead heading? I just mow them down with a weedeater. The giant tubers they grow send up all new lush foliage. If no frost they do that all year.

Thank you. I kinda imagined they might need some kind of brutal treatment. In the meantime I'll just let the seedlings take over. PS don't ever make the mistake of growing these in anything other than pots. They are one of the biggest thugs in the garden! Good luck! Ian