Every article I've read about Flame Weeding says that the "trick" or "technique"
is not to burn them to the ground, but rather to pass the flame over the leaves
for split second. Just enough to basically heat up the water and pop the cells.

OK, that make sense as far as killing the weed (sometimes only temporarily) but
none of the articles say anything about *why* you don't want to burn them to a
crisp. Other than wasting a little propane, and assuming there is nothing else
nearby that the extended heat might bother, why not make them disappear
completely the first time through? I doubt they'll come back any sooner and
things look better immediately.

(Guess who just scorch-earthed the area around his picnic table?)