Shrubs and large grasses would do it. Look at Viburnums, and in 6A you can grow some of the evergreen ones like V. pragense (there are others). Look at Miscanthus grasses--there are several to choose from. Also consider Ninebarks (Physocarpus). Easy project even for a beginner. Just make sure you plant them at least 6-8 feet from the fence.

A few general considerations first. IME shrubs are less work than the majority of perennials as long as you look up the mature width (rather than just what the tag says) on a reliable site such as the Missouri Botanical Garden’s Plant Finder and plant accordingly so pruning isn’t needed. Regardless of what you choose, have repetition of at least some of the plants to provide cohesion, either by repeating a particular large plant several times down the row, or having large grouping of several kinds of plants, or even having a fronting row of a lower perennial such as Nepeta/catmint (sun) or an overall groundcover such as Veronica ‘Georgia Blue’ which is happy in full sun or full shade. I would also make the bed deep enough so that there is a gap between the plants and the fence at maturity for ease of maintenance. If you allow enough depth for a couple of rows of plants such as one of shrubs and one of bulbs and easy care perennials, you can have a really long season of interest.

Here is a winter photo of one of my beds that is a mixed shrub bed , though much larger and denser than you want. It shows the first type of plant repetition, with evergreens that really stand out in winter, each kind in several spots down the bed. Some of the large perennials that repeat can also be seen in their winter shades of gray and tan.

Here is a link to a perennial garden that repeats, both groups of the same plants as well as repeating similar flower colors in different plants. It would take more maintenance to do this with perennials as illustrated here, but the concept of repetition will work regardless.

[https://www.houzz.com/photos/clamshell-alley-rustic-landscape-portland-maine-phvw-vp~20985226[(https://www.houzz.com/photos/clamshell-alley-rustic-landscape-portland-maine-phvw-vp~20985226)

The link below repeats the same 4 plants in a pattern down the whole row.

[https://www.houzz.com/photos/garden-spaces-traditional-landscape-new-york-phvw-vp~3417617[(https://www.houzz.com/photos/garden-spaces-traditional-landscape-new-york-phvw-vp~3417617)

For plants, Consider some of the panicled hydrangeas such as Little Lime or Little Quickfire, both of which will get to around 5’-6’ in about 5 years in good soil in my part of the US, though I don’t know where you are. If you want something larger or smaller, there are other varieties such as Limelight which reaches 9’ or Bobo which shouldn’t exceed 4’. Bloom is long with the QF and Bobo starting in early July and LL and Limelight about 3 weeks later and continuing for the rest of the growing season here. In my NH garden they are fine in all day sun, though at high elevation or farther south than New England they prefer some shade in the hottest part of the day.

If you want some colored foliage, ninebark/Physocarpus has some smaller types such as Tiny Wine with deep reddish foliage and pinkish-white flowers and ornamental reddish seed capsules. They all have a somewhat weeping or mounding shape but vary in size and foliage color- red or green or gold. Gold foliaged ‘Ogon’ Spiraea has white flowers and a slightly weeping shape.

if you will be viewing this from indoors in winter, add at least a couple of plants with winter interest such as a the red twigged, variegated leafed dogwood shrub Cornus Ivory Halo or a smaller evergreen that won’t exceed about 6’, perhaps one of the smaller cultivars of false cypress/Chamaecyparis.

One option to consider for fastening to the fence is the climbing rose Zephirine Drouhin which has scented pink flowers and is virtually thornless. Mine has had healthy foliage for the 5 years I have had it in my garden with no maintenance other than a spring pruning and fastening it to its trellis.

I have emphasized summer interest plants, but you can add spring flowering shrubs that have fall color which as one of the smaller Viburnum plicatum such as popcorn or Newport/‘newzam’ or Fothergilla. You could also underplant the shrubs or perennials with spring bulbs such as Crocus or daffodils.

some ideas:

Thank you very much for all the suggestions and tips. They are very helpful!