Global warming

I love oleander!!! One of the few flowers I can recognize and name. I've seen a awful lot of them in places like Greece, Lebanon, Turkey, Israel, places where I feel at home. Imagine my surprise this spring when I noticed them in Strasbourg. They are not growing wild like in the south, but still: what does a middle eastern flower have to do here, so far north??? They are everywhere now. So, global warming deniers, how do you explain this???