Erlend,
I grew up in Connecticut, and it has similar hardiness zones compared to Norway. I can also attest to the hardiness of Musa Basjoo. I sent my dad some musa basjoo plants about 2 years ago and they come back beautifully from the rhizomes each year. Unfortunately, most of the back yards/landscapes in Connecticut (and most of the northeast for that matter) are very boring. It's all the same thing, pine trees, maples, oaks, rhodedendrums, yews, and maybe an apple or pear tree. I very much enjoy diverse types of landscaping and I am glad to hear people in your country are starting to experiment with things out of the ordinary.
When I travel to Connecticut I too have started to see things out of the ordinary such as bamboo, mimosa trees, and hardy cactus.