Hi SAB
Not familiar with the 'Treason' weedkiller, but have personally had good luck with plain old Yates zero mixed 10:1 with dish soap (a surfacent) carefully paint brushed onto a few of the suckers.
Had really good results with that one.
Other one I have used is Yates tree and blackberry killer, fairly good result
When used properly and carefully, you can't beat glypho
