What about summersweet? How moist is the soil?

I briefly considered clethra, as I think it would do very well in that spot. However, it is so incredibly slow growing and slow to leaf-out that I nixed the thought. I have two in another spot in my yard that have grown at a snail's pace since I put them in several years ago. Unless I managed to hunt down some very large ones from an area nursery (and then pay and arm and a leg for them), they would barely peak up over the height of my deck.

Oakleaf hydrangea if deer are not a problem. Cephalanthus if they are.

It's nice to have you defining 5' as narrow; often it means 1'-3' when someone asks about narrow spaces!

I might wait until after the fence is in to plant here. It sounds like the new fence may change the light levels some, and if the space is just 5' deep you may want the space to put up the fence without having to worry if your new shrubs are going to be trampled on. Fall is a great time to plant.

Deciduous or evergreen rhododendrons might work well.

Fothergilla (scented)

Clematis on a trellis

Daphne x transatlantica 'Summer Ice' (scented)

Thanks laceyvail for the cephalanthus suggestion. I hadn't thought of that. And thank you, Babs, for your sage advice. I am definitely planning on waiting until the fence is up before I plant anything, not only to get a better sense of the light but mostly because I don't want the contractors trampling anything. Since the sunlight that the strip receives comes mostly from the south, I don't think the new fence will interfere with it much. I've been spending my weekends watching how the sunlight plays out on that area, and at most I think the new fence might cut off a tiny bit of dappled sunlight (that is filtered through some trees in the park) in the late afternoon.

I've never grown rhododendrons or azaleas, although growing up we had a beautiful stand of each. I would have to test our soil ph. But we do have fairly heavy clay soil. I suppose I could always do what most people do: plant them shallow and mound them up.

I'm not familiar with fothergilla. I'll have to do more research on that. The clematis idea is great, and I already have several. One of my main reasons for putting in shrubs, though, is because I want to avoid having to mow grass on that strip. I need something bulkier that not only gives height but depth as well. I suppose I could plant more perennials in front of the clematis, but then I lose the four-season structural element.

Based on some other posts I read, I did some research on daphne. They are beautiful, but people complain that they are fickle and difficult to grow. Is that your experience?

Thanks to everyone for the suggestions. My main goal at this point is to develop a short list of possibilities, do more research, and wait until the fence is up until I plant anything. But I love strolling through the local nurseries, and am prone to making impulse purchases when I see something I like. At least this way I'll have a better idea of what might work in that space.

Many Daphne are reputed to be finicky, but I found that D. x transatlantica 'Summer Ice' was quite resilient, sitting in a quart pot for a season when some unexpected foundation work was required, right where it was planned to go. It survived in more than half shade for 6 or 8 years until last winter when the voles ate every root. They had eaten some previously and it had bounced back, but with all roots gone, the plant was as well. Summer Ice has semi-evergreen leaves delicately edged in white and was both the first (except for the witch hazels) and last plant to bloom in my garden and the entire time in between, so if you want a scented plant, it's a good one since it's always wafting a bit of scent. Never spectacular like a rhodie in full bloom, but always lovely in a quiet way. It was in a bed that didn't get water except when something was planted, and got mulched when planted, but only once since then, so mine thrived on benign neglect. I will replace it (planted in an antivole cage) when I find one.

Fothergilla is a two season shrub. Right now it's gearing up to bloom, and is decorative for about two weeks or a bit more. In the fall it's the last plant to turn color, but it's worth the wait. I have ones in full sun and full shade, and the growth is a bit less dense and the fall color a bit less bright but still nice in shade.

You haven't said where you are. I am in New England and have fine sandy acid loam, so you should check you pH to see if my suggestions will like your soil.