I have heard of people canning fiddlehead ferns but do not have instructions for doing so. If anyone has the directions please feel free to drop me a line and let me know about it. Fiddleheads can also be dried in your dehydrator and used at will in soups and stews. I have never dried them myself but was given several from my good friend Richard and they are great. No commercial interest on my part.
Fiddleheads are great in soups.
I love cream soups and whip them up all the time much to the dismay of my hips. Feel free to take this recipe and convert it to a broth soup if you prefer. With fiddleheads it is easier to wash, chop and steam them until tender before adding them to your soup. I generally have this going in one pot while I work with everything else in my soup pot. Feel free to substitute other wild edibles or domestic veggies to suit your tastes and what you have handy.