Q.Ostrich Fern turn brown/black
I acquired a lot of ostrich ferns from someone who wanted to get rid of them. It was in May I think. The ferns were already large. I transplanted them immediately and tried to keep them watered. They have been turning dark and drying up, usually from the top to the bottom. What could be the reason for this and what can I do? I planted them under a tree in the shade in two different areas of the yard. One area gets some sun.

Ferns, especially large ones like the ostrich, send their roots out a long way. Even though you may have tried to dig up a big root ball, most of the roots were ripped away. So your ferns are busy growing new roots. They may have to discard most of the leaves in order to save their resources. It may take awhile, like a couple of years, for them to get their roots under them, but they're awfully tough plants, they should make it. Here's some information: https://www.gardeningknowhow.com/ornamental/foliage/ostrich-fern/growing-ostrich-ferns.htm