Gardening by the seaside has several unique challenges and benefits. The climate may be milder, less prone to frost and snow, but equally coastal gardens are often exposed sites and suffer from sea spray heavy with salt. Many gardens can be second home, and so the garden must fend for itself for periods.
If the garden is very exposed, it may be necessary to create a windbreak to create shelter. A hedge is better than a wall or a fence which can create wind eddies and be blown down. A mixed hedge can be formed from many of the shrubs listed below. If garden pots are unattended for periods, a good tip is to add water gel crystals to the soil, which will help to retain water; good also is a mulch, stones and shells look attractive. Gardens near the sea need tough plants - Below are just a few suggestions depending on your personal preferences; all are suitable for seaside gardens.
There are more ideas with links to detailed growing advice at Shrubs for seaside gardens and plants for seaside gardens.