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Few plants earn their place in a British garden quite as readily as our native ferns. They evolved in the dappled gloom of ancient woodland, so they take the very conditions that leave most flowering plants sulking: deep shade, constant damp, and soil that never quite dries out. If you have a north-facing border, a strip beneath a hedge, or a soggy patch beside a downpipe where little else will grow, ferns will settle in as though they had always been there.
They also earn their keep for wildlife. Unlike the showy doubles and sterile hybrids that fill garden centres, our native species offer genuinely useful cover. Dense crowns of fronds make cool, humid hiding places for frogs, toads and newts, while the unfurling croziers of spring attract aphids, which in turn feed blue tits and their hungry broods. Later in the year, the papery brown undersides of a hart's tongue fern give wrens and dunnocks somewhere to poke about for insects through the colder months.
Start with the two workhorses of British shade. Male fern (Dryopteris filix-mas) is the tough one: it shrugs off dry spells once established and produces a bold shuttlecock of fronds up to a metre tall. It is the fern for a woodland edge or the back of a border where you need bulk.
Hart's tongue fern (Asplenium scolopendrium) is quite different in character, with undivided, strap-like fronds that stay green right through winter. It adores lime-rich soil and deep, humid shade, so it is perfect for a walled courtyard or the foot of a north wall. It also copes better than most with dry shade once rooted, making it a sensible choice under mature trees.
Once those two are thriving, branch out:
Ferns are not fussy about fertility but they are particular about moisture and air. Before planting, fork over the ground to a spade's depth and work in plenty of well-rotted leaf mould or garden compost. If your soil is heavy clay, add grit as well so that water drains freely through the root zone rather than sitting in stagnant puddles, which rots crowns over winter.
Natives look best planted in informal drifts rather than lonely specimens. Set them about 30–45cm apart for medium species, allowing their fronds to knit together to form a continuous canopy. This not only looks natural but also keeps the soil beneath cool and moist, mimicking the leaf litter of a wood.
Plant in spring or early autumn, when the soil is warm and rain is reliable. Water thoroughly after planting even if rain is forecast, and keep watering through the first summer until you see new fronds pushing up.
The single biggest mistake with ferns is letting them dry out in their first year. Aim to keep the soil consistently moist but never waterlogged. A thick mulch of leaf mould, composted bark or spent mushroom compost, applied in early spring, will lock in moisture and slowly feed the plants as it breaks down.
Wind is the other enemy. Strong gusts shred tender new fronds, especially on soft shield and lady ferns, and can scorch the edges of hart's tongue in exposed spots. Site them where a hedge, fence or wall breaks the prevailing breeze, or plant a low barrier of shrubs to windward. If you garden on a blustery plot, stick to male fern and hart's tongue, which are the most wind-tolerant of our natives.
Cut back old, tatty fronds in late winter, before the croziers begin to rise. On evergreens such as hart's tongue and hard fern, remove only the brown, damaged ones and leave the rest intact as shelter for overwintering insects. Divide congested clumps every three or four years in early spring, replanting the outer, younger sections and discarding the woody centre.
Ferns work hardest in a garden when they are woven into a community of native plants. Underplant them with wild garlic, wood anemone and primrose, which flower before the fern canopy closes overhead in late spring. Add a few wood sedge or bugle at the front of the border for nectar in early summer, and let a small pile of stones or logs sit among the ferns as a refuge for beetles and slow-worms.
Damp fern shade is also prime amphibian territory. A shallow saucer of water tucked into the greenery will give frogs somewhere to rehydrate on dry nights, and a hedgehog box nearby will be gratefully used. Avoid slug pellets entirely: the moist, sheltered ground beneath ferns is exactly where thrushes and hedgehogs hunt, and a healthy population of these predators will keep the molluscs in check. The result is a green, quiet corner that asks very little of you, gives back abundantly, and looks thoroughly at home in a British garden.
Opal Glade shares practical, down-to-earth guidance on woodland gardening and british wildlife for readers across the UK.
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