I live all but 20 minutes drive from the sea and I love it. If I'm honest I couldn't imagine life without it or at least the prospect of it. Every season I promise myself I will get more time in the water and every year I get less. I often contemplate a small place around Croyde that I can retreat to in winter and catch some of the waves the grimmer weather can offer.
This, however, is a dream and the one thing I know would upset me is the limited choice of plants. (There are of course lots of plants that will thrive near the sea but very few that will take a spot on the beach.) So with that moan about not having enough surfing time and a lead into plants at the seaside I will endeavour to discuss some of the plants you might like to try and the ways you can get away with more.
As with so many aspects of gardening, there are several rules of thumb that will get you by if you are planning a seaside garden. Your first problem, if you garden by the sea, is that your plants must be able to put up with salt winds. So how do you know that the plant will be ok with a salt wind? It might be the preffered approach of Prince Charles, but I'm afraid a sit down discussion with each subject you like the look of is not going to result in good choices. In honesty it will most likely encourage your eviction from the nursery in a comfortable and secure white van!
What will be useful, though, is the recongnition of features that help prevent moisture loss through foliage: blue/grey and hairy. (Not a comment on the residents of Glasgow but a very good indicator of foliage that will retain good amounts of moisture despite drying winds and salt air.) Some examples are Brachyglottis (Senecio), Nepeta, Lavandula, Eryngium, Echinops, Stachys.
The other thing that is useful to know is that fine-foliaged or needled plants are very good at retaining moisture. This said, it must be applied with some caution. Not all needled and fine foliage plants will cope but many do thrive. To give examples of both, many of the pines love the sea, Tamarix grows beautifully and grasses will seed themselves merrily through pebbles and scree. On the other hand Acer Koto no ito will scream with fear as it approaches the coast.
As I mentioned earlier, the proximity to the sea plays an important part in what you can have in your garden. If you are on the beach with no breaks then be content with the fact you have some prime real estate and that the sea kale, Eryngium and Centranthus are pointers to that fact.
If you are, however, a row or two back from the sea be happy in the thought that your neighbour has sheltered your property from the weather and sea, and that although he or she has more value in their house they can, of course, grow sod all while you have a broader pallette to work with!
One last point before I give a little list of great seaside plants - remember a garden is yours to experiment with. Although some things shouldn't grow there it is more often the case that some plants, which have no right growing in the harsh coastal conditions, will do just wonderfully in a little spot in your garden.
So here is a short list of plants that you could try:
Grasses (nearly all) Tamarix Crambe Lavandula Hebe (some)
Phormium Cordyline Pinus (some) Eryngium Cytisus
Genista Allium Eremurus Olea (sheltered) Osmanthus
Olearia Sedum Rosmarinus Malva Brachyglottis (Senecio)
There are lots more but there's a start.