I knew they were competing for above-ground space, but I bet you're right and the root6s are fighting it out underground. I hate to divide that until I'm confident of my fern-dividing skills. It's the most successful clump I have.
I would rather lift or divide some small fern clumps that popped up where a compost heap used to be. I'll probably practice on a small clump after reading and thinking for a year or so.
I should have taken photos before starting the thread, but "I'll get around to those" soon!.
