A decent place to farm Bruiseweed is at Loch Modan on the Eastern Kingdoms continent. A stack of Bruiseweed goes for 10-30 wow gold in the auction house. If you have flying, Cataclysm and of course the wow herbalism profession you should be able to farm 1-2 stacks of this wow herb in one hour. The best place to farm this wow herb is at Northern Stranglethorn.
The best addon to use for wow herbalism is Gathermate2. If you use Gathermate2_Data you will be able to see all the herb node locations for all the herbs in wow.