https://en.wikipedia.org/wiki/Caffeine#Natural_occurrence https://en.wikipedia.org/wiki/Caffeine#Natural_occurrence Not sure what they're referring to by unrel

https://en.wikipedia.org/wiki/Caffeine#Natural_occurrence https://en.wikipedia.org/wiki/Caffeine#Natural_occurrence Not sure what they're referring to by unrelated plants in 'temperate climates', which I suspect parts of the midwest might be generously described as. I bet you could grow some of the linked items in a garden or smallish greenhouse, though.