yes they appear to be Ostrich ferns, tho I count myself as no hardy fern expert...
5ft is a bit of an exageration, perhaps in the 'perfect' setting, tho the standard height is more 2 1/2-3 1/2

best of luck
drew

I have seen them that tall in certain damp, cool, shady spots in the boreal forest of Saskatchewan - it's quite a sight. "The perfect setting", I guess.

I have one that is roughly 5'. Kansas in the summer time is not MY idea of ideal conditions, but apparently the fern likes it!

Paula

In the full sun and mucky soil they prefer, ostrich ferns will grow to 5 or even 6 feet. As ABGardeneer notes it really is amazing--I haven't seen it since leaving upstate New York several years ago (in my own garden they grow about 3' tall). Considering their natural habitat they do well in ordinary garden soil, but tend to grow much smaller.

I have them around a pond and the ostrich ferns there grow about 3 feet high. The same ferns have spread between a wooden planter and our wooden fence and there they grow to 5 feet high. Of course, that is not where I want them to grow as there is just a couple of inches between the planter and the fence.

You can see the ferns around the pond in the picture below. The pond is located directly behind the ferns you see in the foreground. If you look at the right hand side of the picture against the fence, you will see a few fronds of the 5 foot ferns. The fense is six feet high for an idea of the perspective.

{{gwi:600164}}