Didn't Colorado or another state legalize growing hemp recently? Seems like i heard that one of the states that legalized medical use ... did hemp as well.
Maybe it is around the corner.
I guess Im confused as to what you want to use it for. You have mentioned pasture and prairie.
In regard to sun flowers. If your talking prairie. There are several native varieties to choose from. Be careful as some can be very invasive.
The following was in my mail today. Different use but thought might be of interest.
It is to our eyes, a crime that growing hemp is outlawed in the US.
Hempcrete is a natural building material that can be used for everything from roof installation to flooring to wall construction. It is energy-efficient, non-toxic, resistant to mold, insects and fire.
At least one luxury home in the US (Asheville, NC) is made of hempcrete and getting a lot of attention.
Come join the CNN team for less than 2 minutes and see.
Even the walls and the doors are made out of recycled paper!