The videos I've seen mostly show how to flame small seedlings. Just walk the flame past them, and maybe get a little steam out.
I wonder which slows a weed down more: flaming it so that the leaves and stems are quite injured, or using a scuffle hoe and chopping them flush with the soil level.
I speculate that a plant might send resources from the roots to the heat-damaged areas to try to heal them, and exhaust the root. Hopefully exhaust it MORE than growing anew stem would.
After all, plants have to have evolved efficient ways to come back from having been grazed. That happens more often than fires do! Plants might well have evolved to "give up" after a fire, and rely on seeds to re-start the population.
