Hey, today I found a bug (not sure what caused it) that gives green herbs almost 100% level up chance.
Tested on two herbs - Sorrowmoss (Goes green at lvl 335) and Sungrass (Green at level 280).
Proof:
[SPOILER][/SPOILER]
If you do this you can stay in Swamp of Sorrows from 300-360 herbalism skill and you can go straight to Northrend and don't waste any time in Outlands at all!
I don't know why the skill ups have so high chance (missed only 1 skill up leveling from 280-360 today) but I'm sure it's not intended
However, green mining nodes don't have so high chance to increase your level.
Tested on 17.2.2011, EU retail realm, in a guild with Working Overtime.