Choosing Salt-Tolerant Plants For Exposed Coastal Gardens

Why Coastal Gardens Are So Demanding

If your plot sits within a mile or two of the sea, you are gardening in conditions that would test the patience of a saint. Salt-laden wind scours leaves, stripping the waxy coating that protects them from drying out. That same wind physically rocks young plants until roots loosen their grip. Rainfall is often lower than inland, yet humidity is high, and many coastal soils are thin, sandy and free-draining, leaching nutrients almost as fast as you add them.

The good news is that a surprising range of shrubs and perennials have evolved precisely for this life. They tend to share a few useful traits: thick, leathery or needle-like leaves, a compact or low-growing habit, and roots that cope with drought. Choose them well and your seaside garden can look lush and colourful from March through to November, with very little cosseting.

Shrubs That Laugh at Salt Spray

Structure comes first. In an exposed garden, a backbone of tough evergreens gives you shelter, screening and year-round interest, and everything else becomes easier to grow in their lee.

• Escallonia — the classic coastal hedging shrub. Glossy leaves, pink or white flowers from early summer, and it clips neatly into a windbreak.
• Olearia — daisy bushes thrive on the coast. O. haastii makes a dense grey-green mound with white flowers in late summer.
• Griselinia littoralis — apple-green, almost tropical-looking foliage that shrugs off wind. Excellent for a compact hedge.
• Elaeagnus — silvery leaves reflect light and resist salt; it will grow almost anywhere, including dry shade.
• Hebe — especially the larger, shrubby types, which flower for months and cope with poor, gritty ground.
• Tamarix — feathery, pink-flushed plumes in late summer and a graceful, wind-blown shape.

If you have space for only a handful of plants, put these in first, along the windward boundary. Even a low, semi-permeable hedge can reduce wind speed enough to make a real difference to plants behind it.

Perennials and Grasses With Grit

Once you have some shelter, the planting palette widens considerably. These perennials all cope with salt and dry roots, and most are long-flowering.

• Sea thrift (Armeria maritima) — tight pink pom-poms over grassy cushions in late spring. Perfect for a windy edge or gravel bed.
• Sea holly (Eryngium) — steely blue, thistle-like heads on stiff stems that never flop in wind.
• Red valerian (Centranthus ruber) — self-seeds cheerfully into walls and gravel; pink, white or deep crimson.
• Verbena bonariensis — airy purple heads on tall, wiry stems that move in the breeze without breaking.
• Crocosmia — arching sprays of orange or red in late summer; tough as old boots.
• Blue fescue and pheasant's tail grass — architectural, drought-proof and superb in winter.
• Sedum spectabile — succulent leaves, flat pink flowerheads in autumn that bees adore.

Grasses deserve a special mention. They tolerate wind because they simply bend with it, and their movement adds life to a plot that might otherwise look battered. Plant them in generous drifts rather than singly.

Making the Most of a Balcony or Small Space

Salt wind is fiercer on an exposed balcony, because there is no soil to buffer it and roots are confined to pots. Choose the largest containers you can manage — 30 litres or more — as small pots dry out within a day in summer. Terracotta dries fastest; glazed pots, wood or thick plastic hold moisture better.

Raise pots onto feet so water drains freely, and use a soil-based compost mixed with 20 per cent grit for weight and drainage. Group containers close together so plants shelter one another, and place the toughest specimens at the windy edge. Trailing rosemary, lavender, thyme and Osteospermum all do well in this setting, as does a clipped box or Pittosporum tenuifolium for structure. Fix trellis or a slatted screen to the balcony rail — even a 60cm screen genuinely reduces wind damage.

Soil, Watering and Feeding

Coastal soil is often sandy or chalky, and always low in the organic matter that holds moisture and nutrients. Before planting, work in plenty of well-rotted garden compost or manure, then mulch every spring with a 5cm layer of bark or compost. This single habit does more for coastal plants than any fertiliser.

Water new plantings thoroughly for their first two summers, even drought-tolerant ones. After that, most of the plants listed above will manage largely on rainfall. Feed sparingly: a general-purpose feed in spring is plenty, and generous feeding produces soft, sappy growth that wind shreds. Conversely, over-feeding lavender and rosemary makes them floppy and short-lived.

Practical Pointers for a Windy Plot

• Plant in autumn where possible, so roots establish before the drying winds of spring.
• Stake tall perennials low and early, using discreet links rather than canes.
• Water in the morning so foliage dries before evening, reducing fungal problems.
• Rinse the leaves of container plants with plain water after a gale to wash off salt.
• Plant densely. Bare soil between plants is an invitation for wind to scour the surface and for weeds to move in.
• Accept a little tatter. A few shredded leaves in February are a small price for a garden that sings in July.

Work with the sea rather than against it. Grey foliage, silver leaves, grasses and sturdy flowering shrubs suit a coastal plot far better than delicate woodland planting, and once established they need remarkably little from you. Start with the toughest shrubs on your windward side, add perennials in generous groups, and your seaside garden will reward you for years.