I am excited to have found this web page with species growing at the world's northernmost botanical garden at 65 degrees North latitude in Akureyri, Iceland:
http://www.lystigardur.akureyri.is/?modID=1&id=45&lat=1
its written in Icelandic language, but if you scroll down, the letters a-z give you the latin names of plants growing at akureyri botanical garden. They are at 65 degrees N, still Koppen Cfc (subpolar oceanic), but nearly Dfc(subarctic), and I believe USDA hardiness zone 7. Its especially exciting for me here in kachemak Bay, Alaska, because the summertime climate there is nearly identical to mine here, but about 2 degrees fahrenheit cooler than mine in summer (though slightly warmer in winter), so anything that grows there should theoretically grow here if it is cold hardy enough. This is a great reference for far northern maritime areas and should be useful for people in Anchorage, Southcentral and Southeast Alaska, Aleutians, East and west coasts of Canada, Maine, Scotland, Scandinavia and northwest Russia, and of course Iceland and the Faroes, possibly Greenland. Just compare the hardiness of plants on the list with that of your area. The list itself does not have hardiness, you will have to check that with pfaf.org or another source. I believe everything on the list is zone 7 or hardier. Also, your browser can probably translate the page to English.
here is the wikipedia article on Akureyri with a good climate summary
https://en.wikipedia.org/wiki/Akureyri
I am checking the plants list with pfaf.org and compiling a list of all the plants growing at Akureyri that pfaf has given an edibility rating of 4 or 5, and I'm including some rated 3 if I find them especially interesting. I did the letter A today and collected 23 of the 2 hundred or so whose latin names begin with a on the Akureyri botanical garden species list. If I ever make it thru the alphabet I will publish it here.