I'm looking for some perennial plant suggestions for a very small area in terms of width. I just moved into the home and wanted to get some things planted that would give me a good 3 years before I redo the size and shape of the bed. Currently there is nothing planted there and it just looks bare.

I'm in SE Wisconsin and the area is only 3 ft wide by 25 ft long. It faces south east and is shaded by a large maple tree so it most of it seems like a shade to mostly shade area. There is a 5 ft long clip that is closer to part sun.

I was thinking of trying some black eyed susans in the clip that gets part sun. I've had better luck with them in that condition instead of full sun.

I'm looking for ideas for the shade to most shade areas that aren't the standard hosta and astillbe that might add some color but not be too large for that unfortunate small width.

Can anyone help me out?