That clip has me hooked onto finding out more! Gardener in me is so curious.
The link to the full episode is in that note.
Comfrey outputs the most annual biomass production of any terrestrial plant. It'll increase your compost quality, It's a pollinator haven as it produces hundreds of pink and purple flowers. Chickens like to eat it as well.
"Comfrey outputs the most annual biomass production of any terrestrial plant." How about Bamboo?