During the month of August, I didn't taste a single artificial flavor, that I know of. I'm aware that on at least three occasions I tasted food that I didn't make myself, and I can't vouch for all the ingredients therein. But I'm pretty sure that most of my meals contained only local ingredients, and that included the seasonings.
That meant no imported black pepper. No cumin. No -- er, well, those two are actually the only regularly used spices in my usual cooking that I know aren't grown nearby. To be sure, I'm known now and then to sprinkle cinnamon over "Greek" braised lamb shanks, to mull wine (oh, maybe every 14 years or so) with cloves, to smear wasabi on a fillet of fish... I've got shelves full of dried herbs and spices: Chinese star anise. Mustard seed. Saffron. Ginger.
OK, here's the thing. It's simply not "evil" to use nonlocal ingredients when you have nothing equivalent that grows within your foodshed. Why else did the spice trade of the Middle Ages flourish so? Not only were the difficult-to-obtain flavors exotic (and expensive), they really added something special to certain dishes, something that couldn't be obtained locally.
Or could it? I'm not going so far as to claim that you can recreate the flavor of a Moroccan bisteeya or a Hungarian gulyásleves or a Japanese sukiyaki without the original ingredients. But those original ingredients are not, per se, "native." Some are imported, venerated for ages, and seamlessly incorporated into the national cuisine.
For the Eat Local Challenge, though, I tried to circumvent the need for imported spices. I made a lamb stew, heavy on the carrots to compensate for the absence of "cookie-flavored" spices (clove, cinnamon). I even used carrot tops for additional "green" flavor in place of bay leaves. I used lemon peel in places where I thought it would make a difference. I subbed chili flakes for the heat of black pepper.
I never said I don't use thyme, oregano, rosemary, etc. But I do grow those herbs on the patio. They're not "native." Because I can walk 10 feet out the back door and pick a handful, though, I suppose they're now considered "local."
It's all semantics.
And I've become a bore.