It won't land you in jail, but you could spend significant time waiting in line to be inspected. We had some home grown green beans we brought back from Bowen Island, that the US Customs wanted to see. We waited in line for about 30 minutes, then an inspector carefully examined our entire vehicle while we waited inside the office. Then a few more questions, and we had spent nearly an hour in all. The green beans were OK after they were examined under a microscope.
The day before, I got on the US Customs website to check on green beans, that seemed to be OK to me to bring into the US. I asked the agent about it and she said that the requirements change daily, and it is hard for even them to keep current.
