What is the length of the wall?

I would suggest installing flowering shrubs that do not grow very tall at maturity.

Many hydrangea love partial shade and the dried flowers look nice with snow and ice over the winter. Their blooms will also soften the stone wall. Also consider St. John's Wort (Hypericum 'Ignite'), Bloom-A-Thon Azalea, Chardonnay Pearls Deutzia, and Little Henry Sweetspire as great options too!

With this location being such a prominent focal point of the yard, we'd suggest a few things to make this area pop:

1) The Bed Size/Shape: The wall is the structural/ architectural element to this spot, with that said, instead of mimicking the rigidity of this with the bed line, expand the bed line with an undulating, free form shape to create planting 'pockets' to allow for some more depth, and maybe even a small ornamental tree like a Magnolia or Stewartia! Additionally, we'd suggest a small bed below the wall, for a couple reasons: easier for mowing purposes, and a great opportunity to plug in some seasonal color! (see image below)

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2) Go with a mixed palette of plants that will allow for multi seasonal interest.

A few Spring options: Magnolia, Azaleas, creeping phlox, bulbs

A few Summer Options: Stewartia, Hydrangeas, Ornamental Grasses, Coneflower

A few Fall Options: Stewartia, Itea, Sedums, Ornamental Grasses (we love them!)

A few Winter Options: Stewartia (awesome bark, especially when uplighted at night!), Holly, Hinoki Cypress, Dwarf Globe/Montgomery Blue Spruce, Creeping Juniper, Boxwood

3) When dealing with a mixed plant palette, one of our favorite, and most important things to keep in mind in coming up with the actual arrangement, even in most cases superior to color, is TEXTURE! Especially when viewing the garden from a distance like in your case, texture will allow these combinations to support each other in allowing them to POP, and add depth. Mixing large/course leaf textures (hosta, hydrangea, sedum) with small leaf options (azaleas, boxwood)...thin bladed textures like ornamental grasses are always a great way to increase textural contrasts, or even the contrast of needle/vs fan type evergreen foliage (spruce and cypress for instance)...

Hope this helps!