Sensitive fern

Onoclea sensibilis

In other languages: Onoclea (Nederlands) · Onoclée sensible (Français)

The sensitive fern comes from eastern North America and eastern Asia, where it grows in marshes, wet woods and along streams. It is a sturdy fern about 60 cm tall with broad, pale green fronds whose coarse, wavy-edged segments make it look hardly like a typical fern. Besides this green foliage, in late summer it produces separate fertile fronds with little bead-like balls, which turn dark brown and stand through the whole winter. By means of creeping rhizomes it spreads widely in wet soil. Gardeners use it to green up a wet pond edge or a boggy corner quickly.

Caution: Spreads quickly in wet soil by creeping rhizomes and can crowd out smaller plants. Give it space or keep it in check with a root barrier, and never plant it out in natural waters, wild banks or nature areas.

Updated on 9 October 2026

Light
Partial shade or shade
tolerates little sun
Moisture
Moist to wet
must not dry out
Legal basis
Sand, loam or peat
acid to neutral
Hardiness
Fully hardy
down to -35 °C
Size
0.6 m
tall, 1 m wide

Key facts
Pruning months	March
Height	0.6 m
Native to Belgium	No, planted
Poisonous to people and pets	Not known to be poisonous

Identify

Sensitive fern: how do you recognise it?

Habit: Loose stands about 60 cm tall that spread by creeping rhizomes to 1 m wide or more.
Fronds: Broadly triangular, deeply cut into coarse, wavy-edged segments; often reddish in spring, then pale green.
Fertile fronds: Separate, upright stems with bead-shaped, rolled-up segments; green at first, later dark brown. They stand until spring.
Sensitivity: The green fronds die at the first night frost; the rhizomes themselves are very hardy.
Roots: Branching, creeping rhizomes just below the surface, by which it spreads quickly.

Plants: March–May and September–October · Pruning: March

In your garden

Why grow it?

One of the best ferns for wet soil: ideal beside a pond or stream or in a bog garden.
Broad, pale green fronds that bring freshness to damp, shady corners.
The brown, bead-like fertile spikes stand all winter and look good in dried arrangements.
Quickly forms a dense stand that covers the ground and greens up wet banks.
The dense foliage along the bank gives shelter to frogs, toads and newts.
Very hardy and little work.

Sensitive fern: where does it grow best?

Partial shade to shade; in wet soil it also tolerates more sun, in dry soil the fronds scorch quickly.
Humus-rich soil: sand, loam or peat, acid to neutral.
Wet to very moist: on a wet pond edge or in the marsh zone, where the soil is saturated but not permanently under water. It tolerates temporary flooding.
Give it space: it spreads, so not next to small, delicate plants.
Plant 60–80 cm apart; the group closes within one or two years.

Light: Partial shade and shade
Soil type: Sand, loam or peat
Acidity: Acid or neutral
Moisture: Wet
Size: 0.6 m tall, 1 m wide
Hardiness: Hardy (to -35 °C)

Goes well with

Marsh marigold: Golden flowers in March–April on the wet bank, before the fern fronds emerge.
Purple loosestrife: Purple spikes in summer in the same wet soil, loved by bees and butterflies.
Meadowsweet: Creamy, scented plumes in summer, native and at home in wet soil.
Water forget-me-not: Sky-blue little flowers at the water’s edge, in the same moist partial shade.
Royal fern: A large, stately fern that also likes wet, acid soil.

Maintenance

Sensitive fern: when and how to plant it?

Plant in March–May and September–October.

Plant from March to May or in September–October, when the soil is not frozen.
Dig a hole slightly wider than the pot and work in some leaf mould; in wet, peaty soil this is not needed.
Lay the rhizome just below the surface, at the same depth as before, with the buds facing up.
Leave 60–80 cm between plants. To limit its spread, plant it in a bottomless bucket or dig in a root barrier 30 cm deep.
Water thoroughly straight away and then keep the soil wet at all times.
Spread a thin layer of leaf mould around the plant as a mulch.

Care

Water: Not needed in a wet spot. In a less wet spot, water generously in dry periods: in dry soil the fronds wither quickly.
Feeding: Not needed. A layer of leaf mould in spring is enough; no fertiliser near the pond.
Spread: Each spring or in summer, chop off runners that go too far with a sharp spade.
Fertile spikes: Leave the brown spikes standing all winter; they are decorative and also good in dried arrangements.
Mulching: Leave fallen tree leaves between the ferns; this keeps the soil rich in humus.

Tip: Plant it where it is allowed to spread, such as a wet pond edge, or give it a root barrier from the start. Leave the brown fertile spikes standing in winter: covered in frost they are a real feature.

Sensitive fern: when to prune it?

Pruning months: March.

When: In March, before the new fronds appear. Otherwise it needs no pruning.

How:

In March cut the dead, brown fronds and the old fertile spikes off just above the ground.
For a tidier look after the first frost, you can remove the blackened green fronds in autumn, but leave the fertile spikes.
For a dried arrangement, cut a few brown spikes in autumn or winter.

Caution: Pruning does not keep it small: you limit its spread by chopping through the rhizomes, not by cutting the fronds.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division: Very easy: in March–April cut off a piece of rhizome with a bud and some roots and replant it elsewhere at once. Water well.
Spores: In spring the spores are released from the brown spikes. Sow them fresh on sterile, moist compost under glass; small ferns appear after a few months.

Sensitive fern: how does it get through the winter?

Hardy to −35 °C.

Very hardy, to about −35 °C: no protection is needed in Belgium.
The green fronds die at the first night frost; that is normal and the plant regrows in spring.
The brown fertile spikes stand all winter and give structure to the winter pond edge.
In a pot: keep the compost moist and stand the pot in shelter; a pot in a saucer of water is ideal.

Diseases and pests

Spreading too much: It pops up everywhere in wet soil and crowds out smaller plants. Chop off the runners or plant it with a root barrier.
Brown, withered fronds: In summer, from dry soil or fierce sun. Water generously or move it to a wetter, shadier spot.
Black fronds in autumn: Normal after the first frost: the foliage is frost-sensitive. Leave it or cut it off.
Late frost: The young fronds can freeze in April–May. The plant regrows; cover with fleece if you want to save the foliage.

Through the year

March: Cut off dead fronds and old fertile spikes. Plant or divide.
April: New, often reddish fronds. Plant or divide.
May: Plant. Watch out for late frost.
June: Chop off runners that have gone too far. Water if the soil dries out.
July: Water in dry spells in less wet spots.
August: The fertile fronds appear.
September: Plant. Check the spread.
October: Plant. The fronds die at the first night frost.
December: The brown fertile spikes decorate the winter pond edge.

You and this species

Did you know?

The name ‘sensibilis’ and the English ‘sensitive fern’ refer to the great frost sensitivity of the fronds: they die at the first night frost.
Onoclea sensibilis is the only species in its genus.
Because of its bead-like fertile fronds, it is also called ‘bead fern’ in America.

Garden plants · All species