Here's some research I've done.
Hestia tobacco sells "mostly organic" tobacco. The founder says "much of the tobacco is organic". And that it's because some facilities are not certified but still says it's 'organic'. Check out hestiatobacco.com and talk to the founder David Sley (Ithink that's his name). This company sells only cigs. I break them up and reroll them with organic hemp papers (RAW brand) and with tips.
There are some online vendors which sell Yuma organic, or Manitou organic but since they are shipped from across the seas it's Very expensive, like 30-40 bucks just for shipping. Ends up 60-70 just for one pack.
So, the other two options are whole leaf.
wholesale-cigarette-tobacco.com/Organic-Canadian-Flue-Cured-5-lbs-020.htm is flue cured tobacco also Sells it but you'll have to email them and ask because it's not found on their website for some reason. They sell Organic Canadian Flue Cured Whole Leaf, 30 for 1 lb. He also doesn't usually sell by the pound so he made a special inventory for me on that one.
http://www.wholeleaftobacco.com/ Will be getting organic whole leaf on Monday, so, when that comes you can ask them about it.
Two other Canadian Organic Tobacco sites:
http://www.turtlelodgetradingpost.ca/products/index.php?route=product/product&product_id=110
http://www.turtlelodgetradingpost.ca/products/index.php?route=product/product&product_id=142
Out of stock now, but maybe will later. I also dont know if they ship to the USA.
Herbalfire.com sells pretty Nicotiana Rustica which I found to be superior to any other kind of rustica I've found before. But it just doesn't smoke well since it's probably fermented so it's very strong on the throat, atleast IMO. and makes me feel tired.
And lastly about uppowoc.com : I think the "aroma" is not really liek a additives but I could be wrong. It seems like, if you go into the "Sampler" webpage it says that the tobacco is Packed with a hardwood board. So maybe this is how the aroma is given to the tobacco? It's just hardwood, and I dont consider it to be unnatural. But it's possible that flavors are added and also the hardwood. Who knows. Or it could also be smoked with the hardwood? I dont know. I dont even know if that's good for tobacco. Anyways, I ordered from uppowoc.com the walnut kind... hope it is what I say, ie simply packed with hardwood and not flavored.