Posted: 24/07/2013 at 13:34
I agree about tree ferns and they're also difficult to get through winter without wrapping them up in unsightly fleece and straw. It would also be overkill. I have a bed out the front which measures 7 x 5 metres and can't imagine fitting even one tree fern in it as their foliage spreads so wide when mature. They would also make it very dark in the room that overlooks this bed.
I should think native ferns and similar types would be fine for this situation and aspect and would give great foliage contrast to the hostas, especially if you go for the big boys like golden Sum and Substance hosta or blue and gold streaked June. These can take a year or two to get to mature size so give them plenty of space and make sure the soil is improved with moisture retentive garden compost and/or well rotted manure. You could also add aquilegias and Japanese anemones to extend the season of colour from the bulbs.
Sangko Kaku is a very good acer and the red stems would make an interesting focal point through winter until the new foliage emerges and gives colour through to autumn. I do have one of these in my bed and it's lovely in colour and form.
One word of warning. This bed is going to be a slug fest in spring so start early with wildlife friendly slug pellets on Valentine's Day (easy to remember) and every week or two so you get the perishers as they emerge from hibernation or hatch and before they feed and breed.