In case anyone is curious, the ferns grew back. I did a second cut, but suspect it will keep growning back. The whole area was covered with fern leaves, about 30 inches high, completly blocking out the light to the food plot below. Roughly 60% of the food plot is still alive. I was going to attach a picture but couldn't figure out how. My other plots are doing really good. This plot is going to need a lot of extra attention.