Have you asked about this on the landscape design forum?

Have you considered maybe some dwarf conifers, they can really dress up a space and not take up a lot of room. just a thought

There are some evergreen varieties of Daphne. They're also very showy in the spring and some kinds have berries; I don't know how tall they get; the ones we have here, which are beautiful and variegated, are short. But they would still be nice around the taller plants with bare trunks.

Ornamental grasses would be dead in winter but the dry stalks are still interesting then.

English Ivy is evergreen; if you put that along the fence posts it will add some winter greenery, or maybe if your other bushes are very large, a dwarf ivy can grow right on them and keep them "green" in winter. I think there are non-invasive varieties.

Knock-out roses aren't evergreen but they grow large and will bloom profusely right up to the first frost; I think in your zone that is usually as late as November.

I would use a mix of conifers, evergreen broadleaf shrubs, deciduous shrubs with berries or interesting bark, and late fall/early spring blooming perennials to create a nice balance.