Hi Sandy .. welcome to GoY :o)

I've added your question to GoYpedia All Year Interest and Shade Container plants ... might be some ideas here for you. I hope this helps.

The west facing wall would be a god support for a honeysuckle - the evening sun would bring out the scent.
Hellebores in the shady part would give you early spring flowers and good foliage for much of the summer, and there are some pulmonarias that have really lovely foliage all summer too, and blue flowers (or pink if you must) at daffodil time - many varieties and sorry I don't know the name of the one with the best foliage as I got mine at a summer fayre! If you get sun from about midday pentstemmons would give you flowers all summer. One or two variegated euonymus fortunii for winter colour. Remember it you grow something tall the top will be in the sun long before the roots. Clematis like this so try one on the wall. Tops in the sun give you the illusion of a sunnier spot than you have!
And perennial geraniums are great for this situation and heaps of varieties to choose from.

The first consideration in your circumstances is to choose plants which don't mind a bit of salty air and salt spray, so that knocks out quite a few. Then the choice is down to which ones do better in shadier spots and those which prefer more sun. I'd also ask whether the long beds you have constructed have drainage, or whether they're completely solid at the bottom. Assuming they have got drainage, or at least water is able to get out somehow, there's quite a long list of salt resistant plants to choose from. Here's a list of smaller shrubs (given you've only got 3 feet depth of soil) that might do: Brachyglottis, Calluna (if the soil is acid), Caryopteris*, Ceanothus (thyrsiflorus repens, not the larger ones) Cistus*, Corokia, Cotoneasters (check out C. franchetti and the ground cover ones) Cytisus, Erica, Escallonia, Euonymus, Euphorbia, Fuchsia, Genista, Halimium*, Hebe, Helianthemum*, Hippophae, Lavender*, Lupinus arboreus, Olearia, Parahebe, Phlomis*, Potentilla, Rosemary*, Santolina*, Spiraea, Tamarix, Cordyline. Asterisks denote those that require as much sun as possible.
Perennials include Iberis, Centaurea, Veronica, Yucca (recommend Y. flaccida rather than Y. gloriosa), Geranium (the cranesbill types) Dianthus, Armeria, Artemisia, Aubrieta, Agapanthus, Achillea, Anthemis, Anaphalis, Stachys, Nepeta, Papaver, Penstemon, Phormium (choose smaller varieties such as P. 'Cream Delight', some get 13 feet, check the label for eventual height) Linum, Linaria.
I think that might be enough for you to check out via Google or a good garden book... but I haven't mentioned any annuals or summer bedding, although bedding fuchsias should be fine. Antirrhinums too...

Steragram's advice seems good and what I would also advise but as Bamboo has suggested would you need to consider what kind of plants will be able to tolerate the 'salty' sea air and spray. Hmmm...interesting.

Very helpful answers here ..
good question and replies :o)))