Hi. I don't know much about ferns, but we do have some massive "mounds" of ferns. Earlier this
spring, I divided some of it. Ferns multiply by sending out little roots that look like strings and after 6 or 8 inches, the little root will sprout a new fern. I dug some of the smaller, younger shoots up and cut the root at the skinny part and then transplanted them to a different part of the yard. Lilies of the Valley are the same. Alot of the ferns died because of really hot weather that we had and I wasn't home to take care of them when it got soo hot, but the roots are still doing just fine in the ground and the ferns will come up again next year where I planted them. I hope this helps you a little bit. I don't know what will happen if you keep the fern together. I do know that the massive one that we have is about 7 years old and its HUGE. You can barely walk out that side of the patio because its soo big!!