5 ways to make lots of gold with herbalism at 70 (may not work for all classes)
(1) solo Slave Pens for ancient lichen
No, you dont have to kill anything. Just run through the 1st and 2nd room, learn where the mobs patrol, and harvest all the herbs you can. Average harvest per run = 3-9 ancient lichen, 1-2 ragveil. Repeat 5 times an hour by running out and resetting the instance.
(2) big tree elites in skettis
I dont know how many classes can solo these. Give them a shot, maybe a few shots, use all your abilities and see if you can. Use your herbalism to "skin" these guys. Average harvest = 4 motes of life, 4 ragveil/felweed/terocone/other herb. Also keep your eyes out for other herbs, especially mana thistle up here in skettis, do the bombing run while your up here, and kill a few water elementals for some motes of water. Only downside - very crowded at peak times.
(3) Bog Lord things in zangermarsh
If you cant solo the elites in skettis, no problem. These guys are good too. And the bonus, they are level 61-62, so you can mow through them quickly. Use herbalism on these guys for a good drop rate on motes of life, felweed, other random herbs, and items for zangermarsh rep.
(4) Plain old gathering in Netherstorm
Ride/fly around netherstorm, gathering netherbloom. I just sold 32 for 55 gold, I'm a happy camper right now.
(5) Plain old gathering in Shadowmoon Valley
I havent had a chance to come gather here yet, but I know shadowmoon has its own variety of herbs. I'm sure its just as profitable as Netherstorm.
Now putting it to good use. I'd recommend some type of circuit, maybe something like this (~2 hour circuit, probably 150-200g in herbs, greys, primal lifes and greens)
1) fly to zangermarsh
2) farm slave pens dry, do your 5 minute lichen clears 5 times (25 minutes)
3) either gather in zangermarsh for 35 minutes, or grind on bog lords
4) back to slave pens, repeat process
5) fly to skettis, netherstorm or smv and gather there until you're bored/have to log off