I'm actually using this in my yard right now and it works. A bit slower than Roundup but much better for the environment. Kills weeds in about 48 hours. I don't use Dawn instead we use Seventh Generation dish soap.
The bold succulents in this Spanish-style garden set off the architecture perfectly. By Sandy Koepke Garden and Interior Design in LA. Get Sandy's tips for designing in this style here http://www.landscapingnetwork.com/garden-styles/spanish.html