I'm gonna disagree with what appears to be the majority opinion here.
Just because growing these things is illegal in the US does not mean they are illegal internationally.
Just because we use these things as drugs does not mean they are not plants. They have just as much a place in a garden as any other plant. They'll have the same issues and the same questions surrounding their growth.
And finally it is not our place to judge the grower for their use. Laws change -- especially prohibition laws -- and plants have many uses, cannabis is also used for hemp rope and poppies for baking or beauty.
I think any plant growing, garden tending question ought to be on topic.
Now questions related to using those plants illegally (as drugs, etc) should decidedly be off-topic.