Growing Stevia in Norway

Please advise how to grow Stevia in Norway.

The zone map I have available only shows the southern portion of Norway. The warmest section is zone 7, but to grow it as a perennial out of doors you require tropical conditions. You might have a long enough season to grow it successfully as an annual if you garden no further north than Stockholm (Sweden) You would have to start your plants from seed or cuttings (the former is not easy) early on indoors and plant them out after the last frost date. Harvest one third of the height of the plant in mid-summer and the rest of the plants just before the first frost. Over-winter your stock plants in a cool place and water only lightly to stop shriveling.