There's not much of it in the Wetlands...although there is some where the previous poster pointed out.
The best places I've found for it are Alterac and eastern Arathi, but you're too low for those zones at the moment. Sometimes your trade skills might "outlevel" your character, when that happens, you just have to put them on hold until you get your character up to the level you can continue the trade skills with.
But, I'd check the area in the wetlands that was mentioned above, that's probably your best bet, although its not as abundant there as in the next level tier of zones up.