Hello everybody... I'm an occasional poster to GW but this is my first time in this forum. I have two Polystichum setosum, which I bought doubly labeled as Japanese lace fern and tassel fern (go figure!) Whatever they're called... I planted them in hanging baskets last spring, with some algerian ivy, and added some begonias this year. One of them is thriving beautifully. The other develops healthy fronds, but as they grow, they gradually turn browner and eventually dry up.

The specs: NNE balcony shaded by tree. The baskets are on opposite ends of the balcony but I don't think there are any differences in the light. No pests that I can see immediately. The other plants in the basket are doing fine. Other ferns on the balcony, including a pteris and a boston fern, are doing fine. The only difference I can think of is that I'm watering the other (healthy) polystichum more, because it's closer to the balcony door and I sometimes just chuck my half-empty cup of tea or whatever into it. I tried to even out the watering but it doesn't seem to be helping much.

Any ideas? Is it okay to cut back the half-dead fronds or do I have to wait until they're completely dead? Thanks a bunch.