Early spring, after frost but before the new leaves break, seems to be ideal for most of the ferns in Indiana. Fall should work, too, but I wouldn't try during summer.

Patrick Alexander

Thanks, Patrick, I will wait until Fall. Right now they are large and so beautiful, I sure don't want them to die from transplanting . When I do trnasplant them in the Fall, should I cut them back some?

I would wait until next spring if you can. I've always heard that and it's always worked well for me. paalexan stated it pretty much verbatim.

I would transplant them early fall after it cools off. This way they can get established before the ground freezes and have a head start come spring. I often take ferns to our plant sale in August. At the time of the spring plant sale some of them have not emerged yet.

If you search in and around your large established ferns you should see "babies" getting started. I would dig these and transplant. You could do it anytime if they are small enough and you water them daily for a week or two.