If you never played World of Warcraft before, is a small part of the game is crafting. Different classes, craft different types of items. Two of the classes are scribes and alchemists. Both of these classes to make pink and potions out of flowers. You pick these plants was still called, "herbing" that many people snidely refer to as flower picking. Regardless of the naysayers, Herbing and crafting are great ways to make money and stay well supplied with gold.
To take advantage of the new herbs, and make as much possible gold as possible, easy-to-understand scarcity and ease of finding these new herbs.
Cinderbloom: Cinderbloom is probably the easiest to find. It will be found by a lot of people leveling. As more people level and less need for the urban the prices will drop. Over time once everybody has leveled the difficulty of going back to these herbs will make the scarcity rise and they'll spike back up in value. Saving a fair amount of these, herbs can therefore be slightly profitable.
Stormvine: Stormvine is only found in grassyy areas. That makes this herb relatively rare, and therefore fairly inherently valuable. To locate this herb you can simply look for the grassy areas and remember them for future searches. A couple of really good places are the Twilight Highlands and the northern cliffs of Mount Hyjal.
Ashara's Veil: this herb is very valuable but may not be worth the effort to farm. If you buy in bulk cheap is worth purchasing the farming it takes too much time. It is only found underwater in the specifically very plentiful near the home of Lady Azshara. Movement underwater is so slow and sluggish that makes gathering this herb quickly enough the pain that is not worth your time.
Heartblossem: this herb may be the highest level, but it is certainly now forming for. The price will surely drop over time as it will be accessible to most higher-level characters to easily acquire it. It is very plentiful. It can be used to great effect for milling since it creates a high level of uncommon quality ink. But outside of this use is to plentiful and easy to acquire to make it worth any thought of farming this plant which can be found all over.