sometimes ostrich ferns are difficult to find. Some people say the ostrich fern are the ones that deliver the fiddle heads (yum), while I am not sure if it is the same fern, eating the wrong fern could be not good.

Try Parsons Garden Center on MDI, I have found them there every year in large quanities, located on MDI.

What about hostas? or goats beard dwarf- aruncus?

Do you want something that dies back every year and exposes the sight, or the snow takes care of the rest of the year.

Yes, Ostrich Ferns are Fiddle Heads and they will grow REALLY tall when given a nice shady moist area! As in 5-6 feet tall!!!! are how tall the ones are that I transplanted many years ago. I wanted them to be a border on a path to a woodland wildflower garden. I planted them a few inches from the edge of the path, needless to say the path was taken over...they are yummy, but if you do not know what you are picking best not to, I understand a brecken fern will make your really sick.

Unless you want a jungle best to pick another...

In a shady area something natural, like a stone wall around the concrete block, would look very nice. Then you can plant various shady perennials in front of the stone wall. The stone wall would also hide the concrete when the perennials die back for the year.

Osmunda cinnamomea, Osmunda claytoniana, Athyrium felix-femina would be nice, too. They have the added bonus of being native to the area and are therefore, about as tough as nails.

My "Interrupted" ferns (Osmunda claytoniana) attain 4-5' every year, the cinnamons are smaller, Athyrium is a bit smaller, too.

Ferns are a lovely choice, you could combine them with Hostas and Alchemilla mollis for nice leaf effect, and I adore Aruncus (great suggestion). It would be a bullet-proof combination.