The Coastal Garden
Coastal situations are widely various, they range from palm-fringed beaches and mangrove swamps, mudflats and estuaries, through fjords and storm-tossed cliffs.
However, they do share some features: a milder climate than the hinterland, with extremes of heat and cold moderated by the sea; exposure to wind and salt spray; sandy or rocky soils with little organic matter and a proneness to drying, compounded by salt. These qualities are associated with steep rocky slopes facing the sea and the elements.
Coastal regions have useful resources: fish, shellfish, edible seaweeds, seashore plants, such as samphire, and fruits from seashore trees, such as elder or beach plums. However, pollution from sewage or oil is an ever-present danger. Local native species offer a good guide to your choice of plants.
Watch out for halophytes—they tolerate drying out and share a great deal with many desert and mountain plants. They usually have silvery or fleshy leaves and a bushy, dwarf or creeping habit; they do well in garden soils but will survive salty onslaughts better than other plants.
"Ordinary" plants need shelter from the wind and from the salt and sandblasting it can bring. You can provide this shelter either by sinking parts of the garden and using the excavated material to raise a bank on the windward side; or by erecting windbreaks (see ***). Solid walls generate turbulent gusts on their leeward side and so cause more problems than they solve.
If they already exist, they should be complemented with trees and shrubs to break up the force of the wind. You need to soften a windward bank by growing appropriate plants on the lee.
Naturally tolerant plants, such as Sedum spectabile, Achillea, and Gypsophila, are best for typical sandy coastal gardens. Some habitats, such as dune slacks, encourage moisture-loving plants, such as Filipendula .
If there is no bank, new windbreak plants will need protecting with a wind-porous fence of some kind, or at least a screen of brushwood supported by stakes driven into the ground.
Arrange the plants densely for mutual support and feed; water, stake, and mulch then at the beginning; but after a year or two leave them to sink or swim. You need to think ahead to the final height of any mature trees if part of your reason for living where you do is the view of the ocean.
Most trees that are suitable for windbreaks do not produce edible crops—although they can look good. These include various willows, evergreen oak, wild privet, Escallonia, Griselinia, and Eleagnus. Behind them you can plant conventionally useful trees and shrubs, such as sweet chestnut, sloe, strawberry tree, sand cherry, Satnbucus racetnosa, Sorbus dontestica, and S.aucuparia "edulis", and aromatics such as rosemary, bay, and lavender.
Within the protected, one, the easiest edibles to grow are often those with wild cousins on the other side of the hedge: carrots, cabbage, seakale, asparagus, fennel, and almost any member of the goosefoot family—spinach, beetroot, and purple orach, for instance. In addition, if the soil is light you can plant garlic, onions, shallots, potatoes, and horseradish, but these will still need mucking, watering, and weeding/mulching to get good yields!
It is a good general principle to grow dwarf varieties, rather than ones that might get blown over, although a good thick clump of Jerusalem artichokes will survive strong winds and will serve as a windbreak for other crops.
Another idea is to erect a sturdy frame for a climbing crop on the windward side, ideally in a V-shape with the point facing the wind. The frame can support such climbing annuals as runner beans or vining squash, or such perennial vines as passionfruit, kiwi, hops, grape—or soft fruit canes as used for growing red and blackcurrants.
Windbreaks are a vital feature of any coastal garden because they protect the house as well as the garden's crop plants and flowers. If the garden has sand dunes, they should be stabilized with plants such as marram grass, with bramble thicketsgroum in the lee.
Windbreak trees should be chosen to diffuse the force of the wind and create a cairn area in front of the house for cultivation.
