Planting Bulbs for Spring Colour by the Sea

Why the Coast Changes Everything About Bulbs

Gardening within a few miles of the British coast is a distinctly different craft from gardening inland. You may have noticed that your garden rarely suffers the hard, penetrating frosts that stop play in the Midlands, and yet plants that flourish a few streets back seem to sulk near the sea. The reason is the combination of salt-laden wind, free-draining sandy or stony soil, and bright, unfiltered light. Winter gales can shred soft foliage, and drying winds pull moisture from leaves faster than roots can replace it.

Bulbs, happily, are built for this. A bulb is a storage organ packed with everything the plant needs to throw up leaves and flowers before the soil has properly warmed. Planted at the right depth, in ground improved with grit, they will sit quietly through the worst of the weather and reward you with some of the most reliable spring colour a coastal garden can offer. Native and near-native species, in particular, have evolved to cope with exactly these conditions.

Choosing Bulbs That Can Take the Wind

The first rule by the sea is to avoid anything tall, top-heavy and top-heavy in flower. A delicate, long-stemmed tulip will be flat on the ground after the first March gale. Look instead for short, stiff-stemmed varieties and species that naturally grow in exposed, grassy places.

• Narcissus (daffodils) — the backbone of any coastal spring. Choose shorter cultivars such as 'Tête-à-Tête', 'Jetfire' or the native Narcissus pseudonarcissus, the wild daffodil or Lent lily. They shrug off salt spray and multiply freely.
• Alliums — Allium hollandicum 'Purple Sensation' and Allium sphaerocephalon stand on wiry stems that bend rather than snap, and their seedheads hold shape well into summer.
• Camassia — tough, upright spikes of blue that enjoy damp-but-draining ground and tolerate wind better than most.
• Erythronium — the dog's tooth violet, a woodland native in parts of the UK, thrives in the light shade of coastal gardens and flowers early, before the worst gales arrive.
• Galanthus (snowdrops) — the common snowdrop is bulletproof. Plant them in the green in spring if you can, as dry bulbs resent disturbance.

If you want tulips, choose the short Darwin hybrids or species tulips such as Tulipa sprengeri or Tulipa tarda, and plant them somewhere with a little shelter from the prevailing wind.

Improving Coastal Soil Before You Plant

Most coastal soils are light, stony and quick to dry, which is excellent for drainage but poor at holding the moisture bulbs need while they are in growth. The answer is not to enrich the whole border but to treat each planting hole individually.

Dig a hole two to three times the depth of the bulb. Into the bottom, place a generous handful of horticultural grit — about a 2cm layer — and mix it through the soil at the base. This creates a drainage sump so the bulb never sits in cold, wet compost, which is the single most common cause of rotting. Then mix the excavated soil with a little garden compost or leaf mould and a scoop of grit, and backfill around the bulb.

If your soil is heavy clay rather than sand, the grit matters even more, and you may want to plant on a slight ridge or in a raised bed. Whatever the soil, avoid fresh manure — it burns bulbs and encourages disease.

Depth, Spacing and Timing

The old rule of thumb is to plant at three times the bulb's own height. In coastal gardens, err on the deeper side, because deeper planting keeps the bulb cooler, anchors it against wind-rock and reduces the chance of it being heaved out of the ground by frost.

• Large daffodils: 15–20cm deep, 10–15cm apart.
• Small narcissus and species tulips: 10–12cm deep, 8–10cm apart.
• Alliums: 10–15cm deep; the bigger the bulb, the deeper.
• Snowdrops and erythronium: 8–10cm deep, in informal drifts.

Planting time is September to November for most spring bulbs, with daffodils going in first as they root earliest. Tulips can go in as late as November or even early December — they benefit from a cold spell and are less prone to disease when planted late. Group bulbs in odd-numbered drifts of at least seven to fifteen rather than in single, lonely rows; the mass gives them mutual wind protection and looks far better.

Planting in Pots, Borders and Grass

Containers are a gift in coastal gardens, because you can move them out of the worst of the wind and control the compost entirely. Use a loam-based mix with added grit and ensure the pot has plenty of drainage holes. Raise pots onto feet so they never stand in a saucer of water.

In borders, plant bulbs among low, evergreen neighbours — hebe, lavender, santolina or hardy geraniums — which camouflage the yellowing foliage while it dies back and shelter the emerging shoots. In grass, choose a rough, unimproved patch and let the leaves ripen for at least six weeks after flowering before you mow. Native daffodils and camassia naturalise beautifully this way and need almost no attention once established.

Looking After Them Afterwards

After flowering, deadhead the seed pods so the plant puts energy into the bulb rather than into seed, but leave the leaves completely untouched until they have gone yellow and limp. This is the single most important thing you can do for next year's display, and it is where many coastal gardeners come unstuck — the temptation to tidy up early is strong.

Feed once with a high-potash fertiliser as the flowers fade. In very sandy soils, a light mulch of compost in autumn helps retain moisture and keeps the bulbs cool. Divide congested clumps every three or four years, replanting the largest offsets at the correct depth. Do that, and the same bulbs will go on lighting up your coastal spring for a decade or more.