Learning Northrend Herbalism
Go to Northrend and learn Northrend Herbalism from one of these trainers below:
You can learn it from Dorothy Egan. (Northrend, not Legion Dalaran)
1 - 50
If you have the [Sky Golem] mount, you should use it while leveling herbalism because you can pick herbs without dismounting.
I just usually follow the yellow route because it's large enough to allow the herbs to respawn at the start, but I included an alternative route marked with red for those who would prefer to farm the whole zone.
The route is easy to follow and the herbs will respawn by the time you do a full lap.
50 - 75