There are various meaning of fern. It depends on how you perceive them. They can be a sign of confidence, trance, secret, magic, charm etc. some people even show their bonding of love for their closed ones through fern tattoos.
They look very attractive as a tattoo art. Most of the people have it on those parts of the body that are visible to the world. There may be a personal thing attach to the fern tattoo while other do it for style and trend.
If you also want to spread the magic of fern on your body then you should surely go for fern tattoos.