Definitely an odd planter! Shows how much the architect or builder knows....but that is a different discussion.
Looks like all shade so limited there. As it is your front entrance, would think you would prefer an evergreen. I have 2 rectangle concrete planters on my front porch rail (north face). I can do impatience, then is just dirt all winter, and can turn into the neighbor kitty-box. Yuk. I put in ivy and was very pleased. One year it got aphids or scale or something, can't remember, and yanked it out, cleaned out dirt, put in more ivy. It stays pretty through the winter and all year. You do need to remember to water, even in winter! I think I killed the last batch from not watering. Me Bad!
I am trying Pachysandra (spurge) in one now. A bit of ivy (variegated) showed life in the other, and got more to go with.
I would also check the ferns as someone suggested. See if there are some evergreen ones, especially if you want year around showing in that spot.
Another issue is the dirt. Especially if the house had been vacant, or nothing planted there, could have been a kitty-box and whatever else. I would dig out dirt at least 1 ft down, see what the rest looks like, and add fresh.
Let us know what you work out!