I have had this boston fern for a couple of years and it has done amazingly... just keeps getting bigger. I repotted it one year ago and it survived a house move. Recently I noticed it was getting a big brown in the underneath leaves ( i have never pruned it and just let it do its thing). I started to lift back leaves and there was a lot of brown and dead as well as at the roots (see pics). There is still lots of green and there are fiddles and new growth in the middle but i am wondering if its pot bound and needs to be replanted in something bigger? or perhaps divided out into two separate plants? what should I do? it is my favorite and I really want it to continue to thrive. Thanks!!!