It's the tail end of the year, the ferns are starting to look brown and 'orrible, so if you have not already done them, it's time to cut them back.
As with most annual herbaceous pruning, my motto is "do it once, do it hard".
Talking of which - slight digression here - it drives me mad when people chop the tops off their herbaceous perennials when they have finally finished flowering, leaving about 2' of stalk jutting up. Why? Why? It's halfway between dead-heading and proper pruning, it looks terrible, and you only have to go round and do it again. And when I say "you", you know that I mean....
So just do it properly the first time: prune back the flowered stalks of your herbaceous perennials right down to the ground. This includes plants like Asters (Michaelmas Daisy), Phlox, Japanese Anemone, etc. And even more than the dying 2' stem, I hate the knuckle-spearing 3" stems: you know what I mean, where people chop the stems, usually at a sharply-sloped angle, just at that height that, when you are instructed to clear out the debris, they can cause pain and anguish by stabbing your knuckles. Grrr.
This also applies to Ferns: here is a classic case of a fern that was cut back not-quite-hard-enough:
What a waste!
To me, one of the joys of late spring is watching the ferns beginning to unfurl those elegant, complicated new fronds (leaves), and the way they open up from a tight, unpromising brown knob.
How can you see that, with all this dead brown matter in the way?
In the case of this poor thing, (which is actually a photo from last spring) I had to spend ten minutes carefully and delicately cutting out those short brown stems without damaging the tender unfurling new fronds. Then I had to try to gently rake out the debris, again, without damaging the new growth.
It's an awful lot easier to just do the job right the first time: so when you cut back the dead or dying parts of your ferns, go right back down to the base before you make the cut. You won't hurt the next year's fronds, they are barely forming at that point - and no, they don't need frost protection unless you live in a really, really cold part of the country: and if you do, you would do better to flop the entirety of the dead fronds over the base, starting at the middle and working round and round, to at least make a neat bundle of it.
Here's one I did earlier, at the half-done stage:
This reveals the tightly-packed brown "knobbles" of next year's new fronds, safely wrapped up for the winter.
Doing this also gives me the chance to rake out some of that horrible moss and other rubbish that tends to accumulate within the centre of large ferns like this: and I'm a great believer in raking out the rubbish!
Here's the finished job, but before I tidied out all the moss:
So there you have it: when your ferns start to look brown and tatty, get out there with the secateurs: cut once and cut hard: then sit back and wait for spring!