said by KrK:
Round-Up I was under the impression is 1) Expensive
2) Not environmentally friendly, and 3) Works on weeds but not on grass and stuff (which I need to kill too in the concrete.)
1) depends on what you consider expensive
2) since vegetation is part of the 'environment' and Round-Up kills all vegetation, one could say it's bad for the "environment".
3) it is a non-selective herbicide... kills all plants**
Given our daily chances of rain this time of year, you'd be better off applying one of the consumer products that 'works' quickly vs the slower commercial products.
**some 'woody' plants are somewhat resistant, but I doubt you have many of those growing in your driveway cracks.