Why can I learn it at level 78 but can’t pick anything until level 80? Am I missing something? Maybe I’m trying to pick the wrong stuff? I’m in Uldum trying to get my cataclysm herbalism to level 25 so I can use lifegiving seeds. Curious about those too. Do they disguise you from the enemy? I’m just doing it for fun but I’m curious 
hmm I haven’t looked at old world stuff, but would it be cata was higher lvl then 78? when the revamp goes live I don’t think that will be an issue anymore
Have you tried using something that bumps your herbalism, like an older glove enchant?
Or using a Gnomish Army Knife.
I do use a Gnomish Army Knife but it doesn’t matter. It’s telling me my CLASS level needs to be 80 but I can learn it at 78.