So reading through these posts I can see the issue is quite a bit more difficult that immediately apparent.
Personally, I have no problem whatsoever with weeds growing in my driveway gravel, I like that it holds the gravel together, cuts down on dust and I just prefer just about anything green to pure gravel. Mine gets mowed regularly and the weeds are lucky to get past an inch tall.
But if eliminating weeds is the goal, I can only think of 3 options.
Option #1 is of course the vinegar route as has already been discussed. I suspect this will require multiple rounds for weed elimination.
Option #2 would be the flame weeded. This is my preferred option, but it too will take repeated applications.
Option #3 would be to starve the weeds of something they need. I was thinking that maybe they could be starved of sunlight.
Many years ago I traveled Wisconsin where my wife’s uncle was having a family reunion. The lived on a lake and even had a boat dock and small beach area. The problem with the beach area was that all sorts of aquatic plants grew right in the best, sunny spots, but nothing grew by the dock which had a cover for a boat. Their approach was to occasionally spread 2,4 D pellets to inhibit the plant growth. So many aspects of this sounded revolting. I hated the idea of spreading poisons. Worse, these would be incredibly mobile, far worse than
lawn applications (and that is bad
enough!). Also I was just imagining that I would be swimming in diluted poison! Ick! Further, the results were only temporary.
My suggestion was to extend a tarp over the beach area when not in use (it was a small area and easily accomplished). Actually they were quite receptive. They could see that weeds were not growing in shady areas. I still don’t know if they took this approach, but would it be at all possible to deny the troublesome plants light? Maybe shade along with other controls could work?
Just my thoughts,
Eric