Why grasses earn their place by the sea

Coastal gardens ask a great deal of their plants. Salt-laden gales, thin sandy soil that drains before you have finished watering, glaring reflected light off the water, and a wind that rarely stops for long. Ornamental grasses answer all of it with remarkable grace. They bend instead of snapping, their narrow leaves lose little moisture, and many of them evolved on dune edges and exposed steppes where conditions are just as brutal as anything a British seafront can throw at them.

There is an aesthetic argument too. Nothing else in the garden captures movement so well. A stand of grass catches the light and shifts with every gust, which means a coastal border that might otherwise look battered and static comes alive. Planted where low winter sun sits behind them, the flower heads and seed heads glow like filaments. For a garden on a windswept plot, that is worth more than any number of stiff, sulking shrubs.

The toughest performers for exposed plots

Start with the plants that have already proven themselves on cliff tops, sea walls and dune fringes. These will shrug off salt spray and stand up to wind without staking or cosseting.

• Blue oat grass (Helictotrichon sempervirens) — steely blue, evergreen, and exceptionally wind-tolerant. It needs sharp drainage above all else, so plant it on a slight mound if your soil holds any moisture.
• Pheasant's tail grass (Anemanthele lessoniana) — green in summer, turning copper and orange through winter. It self-seeds gently and looks superb spilling over a low wall.
• Blue fescue (Festuca glauca) — small, dense and endlessly useful at the front of a border or in gravel. Plant in generous drifts, as single plants can look lost.
• Marram grass (Ammophila arenaria) — the native dune binder, with deep roots and grey-green leaves. Best kept to a wilder corner, as it spreads enthusiastically.
• Calamagrostis x acutiflora 'Karl Foerster' — upright, architectural and reliably sturdy. Its buff seed heads hold their shape right through winter.
• Deschampsia cespitosa 'Goldtau' — a compact tufted hair grass with airy golden panicles. Happier than most in heavier or damper ground.

Finer textures for sheltered corners

If you have a wall, a hedge or a slope breaking the worst of the wind, you can afford plants with softer, more delicate habits. Give these a spot where they are not taking the full force of a south-westerly.

• Pennisetum alopecuroides 'Hameln' — soft, bottlebrush-like heads in late summer. Cut it back in early spring and it returns reliably.
• Miscanthus sinensis 'Kleine Fontäne' — graceful, arching and late to flower, so it extends the season beautifully. Shelter keeps the foliage looking clean.
• Molinia caerulea subsp. arundinacea 'Transparent' — tall, see-through stems that let you plant right through them.
• Carex comans 'Bronze' and Carex oshimensis 'Evergold' — sedges rather than true grasses, but invaluable for edging paths and containers where salt spray reaches.
• Stipa tenuissima — wonderfully fine and mobile, though it demands really sharp drainage and will seed about freely in light soil.

Planting into sandy, salty ground

Sandy coastal soil is easy to work but poor at holding water and nutrients, so a little preparation pays off handsomely. Fork over the planting area and work in two or three buckets of well-rotted compost or leafmould per square metre. This does not change the soil's nature, but it does slow drainage just enough for young roots to establish.

Plant in spring or early autumn, when the soil is warm and moist. Set grasses so the crown sits slightly proud of the surrounding soil rather than buried, which helps prevent rot in wet winters. Water thoroughly for the first two growing seasons, even on a coastal plot — new plants have not yet grown the deep root systems that make mature grasses so independent. A gravel mulch around the crown keeps the collar dry, suppresses weeds and looks entirely at home by the sea.

If your site is genuinely exposed, give new plantings a temporary windbreak for their first year. A woven hurdle or a line of stout stakes and netting takes the sting out of the wind without creating the damaging turbulence that a solid fence causes.

Seasonal care and the seaside calendar

Grasses are undemanding, but timing matters. Deciduous types — miscanthus, calamagrostis, deschampsia, molinia — should be cut back hard in late February or March, just as new shoots appear at the base. Cutting earlier leaves the crown exposed to winter wet; cutting later risks trimming off the new growth.

Evergreen grasses need a different approach. Do not cut them hard. Instead, in early spring, comb through the clumps with gloved fingers or a small rake to pull out dead material, then tidy the tips with shears. Never cut into the old woody base — most evergreens will not regenerate from it.

Leave seed heads standing through winter for structure and for the birds. Divide congested clumps every three to five years in spring, discarding the dead centre and replanting the vigorous outer pieces. Feed lightly with a balanced fertiliser in spring; too much nitrogen produces soft, floppy growth that the wind will flatten.

Designing with movement and texture

Plant grasses in threes, fives or generous ribbons rather than as isolated specimens, so the movement reads as a wave across the border. Contrast the fine, spiky textures with bold, fleshy foliage — eryngium, sedum, lavender, rosemary, santolina and crocosmia all thrive alongside them in coastal conditions, and all share the same love of sun and drainage. Repetition is the trick: the same grass appearing at intervals ties a long seafront border together and makes the whole garden feel deliberate, even when the wind is doing its best to rearrange it.