Ostrich fern

Sun

Partial to full shade. Morning sun is usually tolerated if the soil stays moist; avoid hot afternoon sun and drying winds.

Water

Keep the root zone consistently moist, especially while fronds expand and during summer drought. Established plants tolerate wet ground but perform poorly in dry shade.

Soil

Humus-rich, moist soil, preferably slightly acidic to neutral. Tolerates clay and periodically waterlogged ground, but avoid stagnant, permanently submerged crowns.

Height

3-6 ft (0.9-1.8 m)

Spread

2-4 ft (0.6-1.2 m) per mature clump; underground runners can form much wider colonies.

Foliage

Bright to medium-green, arching sterile fronds form an upright vase and taper sharply toward the base. Shorter, stiff fertile fronds emerge in the centre, turn dark brown and often remain through winter.

Growth

Fast once established, especially in moist, fertile soil.

Care needed

Medium

• Water deeply during dry spells so the soil does not dry out around the roots.
• Apply leaf mould or compost around the crowns each spring, keeping the crown centres uncovered.
• Feed only if growth is weak; rich soil usually needs no additional fertiliser.
• Remove unwanted runners annually before they establish among neighbouring plants.
• Divide crowded clumps in early spring while dormant or just as the fiddleheads emerge.

Pruning. Cut collapsed green fronds back near ground level after they die in autumn or in late winter. Leave upright brown fertile fronds for winter structure, then remove damaged ones before new growth starts.

Late winter

Clear collapsed fronds without damaging the crowns; retain sound upright fertile fronds if wanted.

Early spring

Plant or divide while dormant or just as growth begins, and water thoroughly.

Spring

Mulch with leaf mould or compost and check for runners spreading into neighbouring plants.

Summer

Water during dry weather and watch for scorched or prematurely browning fronds.

Early autumn

Mark the colony's boundary and remove unwanted offsets while their position is easy to see.

Late autumn

Allow foliage to die naturally, then remove collapsed fronds if they smother smaller plants.

• Plant in broad drifts beneath deciduous trees where the soil remains moist, creating a tall woodland ground layer.
• Use beside a pond or stream, above the permanently submerged zone, for upright foliage against water.
• Combine with hostas and large-leaved brunnera for contrasting leaf shapes in a shaded border.
• Place behind spring woodland flowers, allowing the expanding fronds to conceal their fading foliage.

Garden styles it suits: Woodland, Bog garden, Japanese, Green on green and Pacific Northwest woodland.

Plant it with: Hosta, Siberian bugloss, Astilbe, Rodgersia, Solomon's seal and Siberian iris.

Wildlife: Dense colonies provide shelter for small animals and invertebrates. Like other ferns, it has no flowers, nectar or pollen for pollinators.

• Brown, scorched or prematurely collapsing fronds usually indicate drought, heat or too much sun; water deeply, mulch and provide cooler shade.
• Slugs and snails may damage emerging fiddleheads; check at dusk, remove them by hand and use wildlife-conscious controls where necessary.
• Underground runners can overwhelm smaller plants; lift unwanted offsets with their connecting runners or give the fern a separate planting area.
• Rotting crowns can develop in stagnant conditions or beneath heavy, wet mulch; keep crown centres clear and improve drainage around the planting.

Not known to be toxic to cats, dogs or horses, although species-specific veterinary evidence is limited and it should not be treated as animal feed. Young curled fronds are eaten by people only after correct identification and thorough cooking; raw or undercooked fiddleheads have caused significant vomiting, diarrhoea and abdominal cramps. Do not eat mature fronds or assume other fern species are edible.

Where it spreads. Can spread aggressively by underground runners in moist gardens in the northern United States, Canada and the United Kingdom. This is garden spread rather than a claim of formal invasive listing; it is native across much of northern North America and Eurasia.

• Cinnamon fern (Osmundastrum cinnamomeum)

  Its separate fertile fronds become cinnamon-brown, and sterile fronds have conspicuous woolly tufts beneath the leaflet bases.

• Interrupted fern (Osmunda claytoniana)

  Brown fertile leaflets interrupt the middle of otherwise green fronds. Ostrich fern carries its spores on entirely separate, shorter central fronds.

• Lady fern (Athyrium filix-femina)

  Its fronds are more finely divided and lacy, with spores beneath the green foliage rather than on separate stiff central fronds.

The common name refers to the long, arching fronds resembling ostrich plumes.

Propagation. Divide crowns or detach well-rooted offsets in early spring, keeping roots moist and replanting at their original depth. It can also be raised from spores, but division is simpler for home gardeners.

Accepted botanical name

Matteuccia struthiopteris

In the US and Canada

Native in Alaska, Canada and the lower 48 states.

Sources: GBIF (CC BY 4.0) and USDA PLANTS. The care and design notes are LandscapeGPT's own.