According to the forecast, the mercury is to drop next week, with some sub-zero overnights, not much warmer daytimes and possibly some snow! So yesterday saw the annual tree fern wrapping!
Our tree ferns are quite little ( I couldn't bring myself to purchase the larger ones, and they only grow 1" a year!) and live in the Shade border which, while protected by a wall to their south, can be a bit of a frost pocket.
Tree ferns aren't fond of sub- zero temperatures, although larger ones are apparently able to cope with temperatures of -5 to -10C unwrapped, but im not sure I'd ever risk it, unless the plant was too large to wrap.
Last year, we probably could have got away with not wrapping ours at all, as it was so mild, but I'd hate to have lost them, so better safe than sorry.
We wrap ours in a chicken wire cylinder full of straw with a straw hat sitting on the crown of the plant, a good 10" all round. On top, we add a small sheet of plastic, just to deflect some of the rain and keep the crown of the plant from freezing in case of severe weather. We just leave this year's fronds in place, not cutting them back fully until May or so, when the new shoots start to unfurl.
We use straw as it 'breathes' as opposed to bubble plastic which doesn't. If your tree fern is in a sunny position, plastic could heat up and cause the trunk to rot.
We'll leave the straw coats on until April, when the worst of the cold will be over.