I am trying to control some crown vetch growing out of control. The scope of the job is to keep weeds under control along a fence line. I sprayed with 2% round-up and killed everything but the vetch. It did not even yellow it. I was told to use a 3 way herbicide but I do not want to have to make 2 trips down the fence row to spray for broadleaf and grasses. Any suggestions on what to use to kill of the vetch but would also keep the grasses killed back as well? Thanks in advance and I did do a search on controlling crown vetch.