In my opinion, local police don't go around checking backyards and shit for this kind of stuff. And even if they by some happen chance were in your yard/land and seen them growing, I would say most cops wouldn't know a poppy plant from their asshole, let alone the laws for them. I think they care 100% more about marijuana, but cannabis is very distinguishable to law enforcement. Even if a seasoned officer who knows the laws about poppy plants catches you growing a few (not a whole field) they probably wouldn't arrest you or anything like that. Not saying it's not possible, because if it is illegal you can technically be charged, but the likelihood of it happening is slim to none. Especially getting spotted growing them unless you have nosey neighbors or something. Police officers just don't go snooping around backyards looking for illegal plants being grown (other than like I said more strongly, marijuana).