Why ferns suit a British woodland garden

Ferns are the quiet backbone of the shaded border. They do not shout for attention the way a peony or a rose does, but they bring something no flowering plant can match: the unfurling croziers of spring, the soft green architecture of high summer, and foliage that still looks fresh in November when everything else has collapsed. In a British garden, where so many of us are working under trees, against a north-facing wall or along a damp boundary, they are close to indispensable.

Our native ferns have spent thousands of years adapting to exactly this weather — wet winters, humid summers, long spells of grey light. Get them into the right spot and they will settle in for decades, spreading a little wider each year with almost no input from you.

Choosing hardy ferns for shade

A handful of species will cover almost every situation. Start with these and let them tell you what your soil is like.

• Male fern (Dryopteris filix-mas) — the workhorse. Tolerates dry shade under trees once established and makes a sturdy shuttlecock of mid-green fronds.
• Golden-scaled male fern (Dryopteris affinis) — semi-evergreen, with a yellow-green flush on new fronds and a good winter skeleton.
• Soft shield fern (Polystichum setiferum) — finely cut, lacy, evergreen fronds that look almost Victorian. Wants humus-rich soil and shelter from drying wind.
• Hart's tongue fern (Asplenium scolopendrium) — bold, undivided straps of glossy green. Unusually tolerant of lime and dry shade, so it suits a wall base or the tricky strip under a hedge.
• Lady fern (Athyrium filix-femina) — soft, delicate and quick to establish, but it needs reliable moisture.
• Hard fern (Blechnum spicant) — a dainty native for acid, humus-rich ground, with stiff sterile fronds and narrow upright fertile ones.
• Royal fern (Osmunda regalis) — the big one for a boggy corner or pond edge. Give it a metre or more.
• Shuttlecock fern (Matteuccia struthiopteris) — tall, formal and stoloniferous, so plant it where it can spread or sink a barrier.

Add common polypody (Polypodium vulgare) for walls, banks and mossy tree forks if you want to blur the edges of the garden.

Planting into damp, humus-rich ground

Ferns are shallow-rooted and their crowns hate being buried. Aim for soil that holds moisture like a wrung-out sponge: rich in leafmould, compost or well-rotted bark, but never waterlogged in winter. On heavy clay, fork in a good barrowful of organic matter per square metre and plant slightly proud of the surface, mounding the soil so water drains away from the crown.

Autumn and early spring are the best planting times, while the soil is damp and cool. Space plants according to their eventual spread — 40 to 60cm apart for most, a metre or more for royal fern. Water them in, water again the next day, and once more a week later. Keep them well watered through the first summer, and give them dappled shade: a few hours of morning sun is ideal, but hot midday sun will scorch the fronds and dry the soil.

Shelter matters as much as shade. Wind shreds soft fronds and turns a handsome clump ragged by August, so plant delicate species where a hedge, fence or mature shrub breaks the worst of it.

Watering, mulching and feeding

Once established, ferns are surprisingly self-sufficient, but the first two years decide how good they look. Water deeply rather than often, soaking the ground in dry spells so moisture reaches the roots. A blanket of leafmould, 3–5cm deep, spread in autumn will hold that moisture and feed the soil slowly.

Be sparing with fertiliser. A light scatter of blood, fish and bone in early spring is plenty. Rich, high-nitrogen feeds push out soft, floppy fronds that scorch and collapse — tough, leathery growth is what you want. Keep mulch clear of the crowns and never hoe around them; the roots sit just below the surface and a careless fork will do real damage.

Tidying, dividing and pests

Deciduous ferns should be cut back in late winter or early spring, just as the new croziers begin to push. Cut the old fronds to within a few centimetres of the crown and the emerging fiddleheads will have a clean run at the light. Evergreen ferns such as shield fern, hart's tongue and polypody are treated differently: snip out only the damaged or exhausted fronds in spring, leaving the good ones to carry the winter.

Divide congested clumps every three to five years, in early spring before growth starts. Lift the crown and split it with a spade or two back-to-back forks. Slugs and snails will nibble the soft new croziers, so patrol at dusk with a torch or set a barrier of grit or wool pellets around the plants. In pots, watch for vine weevil grubs on the roots — tip out and check if a fern suddenly wilts.

Planting partners and texture

Ferns are at their best layered with other shade lovers. Underplant them with snowdrops, wood anemones and bluebells for spring, then let hostas, pulmonaria, brunnera and epimedium carry the season on. Where the ground stays damp, astilbe, rodgersia and primulas make fine companions; a log pile, a mossy stone or two and a few clumps of moss will tie it all together.

Design-wise, repeat the same fern through a border to create rhythm, and contrast shapes: the bold straps of hart's tongue against the filigree of a soft shield fern, or a stately shuttlecock fern behind low mounds of heuchera. Do that, and your woodland edge will look lush, layered and green from the first crozier to the last frond.