I’m often asked, can rabbits eat ferns? Because I let mine run around in areas where there are ferns growing. The problem with answering this question is that there are lots of different types of ferns. Some are in fact toxic to bunnies, while some are fine if they have a little graze on them.
It’s the same as when people ask me if rabbits can eat fruit, dried fruit, or flowers. There are just too many different fruits and flowers around to answer this question with a blanket answer.
The asparagus fern is supposed to be very toxic to bunnies for example. I’m not sure how common they are where you live or if you even know what they look like, but you should avoid these. Domestic rabbits don’t have the same instincts as wild rabbits and are much more likely to eat something that’s harmful to them.
My advice is to try and keep your bunnies eating all the stuff that’s good for them and avoid letting them trying anything you haven’t checked out fully. It’s not worth the risk.