Here on the coastal zone 8, the best time to cut back sword ferns is in the very early Spring before the fronds begin to produce. Taking care when cutting each with dried orange bits sticking up & around the fern as close to the base as possible to keep from looking unsightly.
Some advise to start cutting back ferns in late Winter but I prefer to wait until Winter is completely over & Spring begins. At least after risk of any more snow fall.
Same for Roses & Hydrangeas. Roses can have a third cut back before Winter sets in if height is an issue, risking the root ball from lifting in a wind. Otherwise very late Winter to early Spring, when buds are about to begin to swell is the time to prune rose bushes. Cutting back hard just before Winter risks some die back with Winter cold.
Hydragena are also left until Spring, as bush is about to bud, cutting just above a bud that has or is ready to begin to swell.
A couple of reasons to wait until Spring for Hydrangeas is because some enjoy the amazing everlasting flowers that begin to dry naturally but most importantly is that leaving all flowers & lengthy branches of Hydrangeas helps protect the plant as a whole for when it snows.
The same goes for ferns. When to cut back ferns is either late Winter or early Spring before the plant begins to send up new fronds. That way the core of the ferns have some protection over winter in event of snow fall.