Dryopteris filix-mas 'Male Fern'
Dryopteris filix-mas although defined as deciduous by the RHS has performed like a semi-evergreen fern over winter holding onto the fronds and remaining green throughout winter. This is a traditional looking fern and when mature can reach over a metre in height. This really is one of the larger ground ferns so make sure you plant it with enough room to grow or it will smother anything growing round it.
Large fern that is winter hardy
I have been growing this for many years and was one of the first ferns I have ever grown and found it to be robust and hardy if a little on the large side as it reaches about 4 years old.
The new spring growth really does look this green as the new fronds unfurl and as the fronds age they turn a darker green
Over the very cold winter of 2010 and the long winter of 2013/13 this fern has remained more or less evergreen. Like most large ferns they can suffer damage to the fronds from the sheer weight of snow settling on them. Once snapped and broken it looks untidy.
Heavy snow is not a friend to large ferns, smaller ferns are less brittle and so can bend under the weight so if this is a problem then just go for smaller ferns. I can strongly recommend Dryopteris erythrosora which is very hardy, evergreen and has some nice red-pink colouration on new growth.
In spring when you see the knuckles of new fronds starting to emerge I have found cutting off the old foliage leads to stronger new growth. It looks great with the bright green new growth especially compared to the darker winter colouring of the previous years growth that remains through winter.
I also grow the closely related Dryopteris filix-mas 'Cristata' which doesn't grow as large, probably about half to two thirds the size but it's well worth growing for the crested frond ends it produces.