What/when to trim 'evergreen' ferns?
When do you trim "evergreen" or "semi-evergreen" ferns like Dryopteris? Do you remove all the old growth in early spring or just cut out the worst of it?
What about the Autumn Fern, for example? A lot of the fronds are still greenish but not exactly great looking. Does leaving last years growth on help on the plant start in Spring, or is it just irrelevant to the plant? Does cutting off the old growth encourage new growth?