(Pic Source: "Hanfstengel" by User:Natrij - Own work. Licensed under Public Domain via Wikimedia Commons)
So, at one time, hemp was grown in the United States. No issues, at least not that I'm aware of. And, it was grown much like cotton and tobacco and was a very nice cash crop. So, what could have happened to cause our government to feel the need to outlaw hemp?
Of course, a quick google search explains: Big Business leaned on US Government to do so.
Why would big business lean on the US Government to ban growing hemp? Well, the short answer is that apparently, prior to the mid-1800's, hemp was used for paper, oil, food, etc. But, it was difficult to harvest it in very large quantities. And, it remained so until after 1930 when a large scale harvesting machine was developed. But, during the period of mid-1800's until 1930, businesses developed other industries for paper (forestry milling) and oil (DuPont) and others.
Then, once the new harvester was designed in 1930, big business fearing the loss of dominance of their businesses, used their power and money to influence our government to ban hemp.
(Source of above info: GreenLeft.org.au)
So, now, to get our CBD Hemp Oil, since we can't grow hemp legally in the US, in order to get CBD extracted from Hemp, we have to import it. Ludicrous. Absolutely LUDICROUS!