Poor drainage

[mumblejumble]

After all the wet weather I discovered that a small part of my garden (I have lived here for 2 months) is quite poorly drained. At the moment it is turfed, but I plan to lift the turf do something about the poor drainage and plant something there as a border. But what?
I am getting more and more confused and have thought about ferns, would they do well there?
Please have to go and feed grizzling ds, but would love some ideas.

[mumblejumble]

Oh yes, it is a West facing wall, catches al ot of sun :)

[mumblejumble]

*a lot
is a fence not a wall. I really want to cover it with a rambling rose.....

[EauRouge]

Ooh, watch Gardener's World on iPlayer, they had a good bit about ferns the other night.

I have heavy clay soil and have improved most of my beds with compost, sand and ash but the bits at the bottom of the slope are hopeless so I've just gone with it. There are lots of plants that like boggy soil. Yellow flag irises do well in boggy soil/a pond (do NOT let them go to seed!). Creepy jenny too but gets very thuggish if you don't keep it in check.