Autumn fern
Dryopteris erythrosora. Family Dryopteridaceae. Fern.
Also called Japanese shield fern, Copper shield fern.
Autumn fern is a clump-forming woodland fern grown for coppery-pink young fronds that mature to glossy green. Despite its name, the strongest colour usually appears with new growth in spring, not autumn. It stays evergreen in mild climates but may lose its fronds in cold winters.
At a glance
- Sun
- Partial to full shade; gentle morning sun is usually suitable, but avoid hot afternoon sun.
- Water
- Keep evenly moist while establishing. Established plants tolerate brief dry spells, but prolonged drought causes browning and poor growth.
- Soil
- Humus-rich, moist but well-drained soil, preferably slightly acidic to neutral; avoid waterlogged ground.
- Height
- 1.5-2.5 ft (0.45-0.75 m)
- Spread
- 1.5-2.5 ft (0.45-0.75 m)
- Foliage
- Evergreen. Arching, finely divided fronds emerge coppery pink or bronze, then turn glossy dark green. Reddish spore-bearing structures develop beneath fertile fronds.
- Growth
- Slow to moderate; gradually forms a broader clump.
- Care needed
- Low
Care
- Water deeply during the first growing season and during extended dry weather.
- Apply a thin layer of leaf mould or compost in spring; routine fertiliser is usually unnecessary.
- Mulch around the plant to conserve moisture, keeping mulch clear of the crown.
- Shelter from drying winds and strong afternoon sun.
- Divide crowded clumps in spring, keeping several growing points and a good root system on each division.
Pruning. In late winter or early spring, cut brown or badly damaged fronds back close to the crown before new fronds unfurl. Leave healthy green fronds in place and avoid cutting emerging shoots.
Through the year
- Late winter
- Remove winter-damaged fronds before new growth begins.
- Spring
- Plant or divide clumps, water thoroughly and apply leaf mould around the crown.
- Late spring
- Check emerging fronds for slug and snail damage.
- Summer
- Water during dry spells and check for scorching where sunlight reaches the plant.
- Autumn
- Top up mulch if needed, without burying the crown.
- Winter
- Leave healthy evergreen fronds standing and check that the soil is not staying waterlogged.
In the garden
- Plant in groups beneath deciduous trees where soil remains reasonably moist.
- Edge shaded paths with arching clumps that soften paving without needing regular clipping.
- Combine with broad-leaved hostas and bergenias for contrasting leaf shapes.
- Use in shaded courtyard containers with drainage holes, where the coppery new growth can be seen closely.
- Repeat through woodland borders for a consistent green framework between seasonal flowers.
Garden styles it suits: Woodland, Japanese, Modern courtyard, Green on green, Low-maintenance and Pacific Northwest woodland.
Plant it with: Hosta, Epimedium, Bergenia, Hellebore, Japanese forest grass and Siberian bugloss.
Wildlife: Dense clumps and retained leaf litter provide shelter for small invertebrates. It has no flowers and supplies no nectar or pollen.
Problems to watch for
- Brown, crisp frond edges usually indicate dry soil, hot sun or drying wind; water deeply and provide more shelter or shade.
- Yellowing and collapse in wet soil can indicate crown or root rot; improve drainage and keep the crown at soil level.
- Slugs and snails can chew young fronds; inspect new growth and remove pests or use a labelled iron-phosphate bait.
- Winter cold can brown exposed fronds; leave them until late winter, then remove damaged growth before new shoots emerge.
Safety
Not known to be toxic to cats, dogs or horses. Human toxicity information for this species is limited; do not eat the fronds or rhizomes, and do not assume its young shoots are edible fiddleheads.
Easily confused with
Male fern (Dryopteris filix-mas)
Usually taller and coarser, with green rather than distinctly coppery-pink new fronds.
Japanese painted fern (Athyrium niponicum var. pictum)
Has silvery-grey fronds with darker, often purplish midribs, rather than glossy green mature foliage; it is deciduous.
The name
The species name erythrosora means red sori, referring to the reddish spore-bearing structures on the undersides of the fronds.
Propagation. Divide established clumps in spring as growth begins. It can also be raised from spores, but this is slow and requires consistently humid, clean growing conditions.
Checked against open data
- Accepted botanical name
- Dryopteris erythrosora
- Native range
- China South-Central, China Southeast, Japan, Korea and Nansei-shoto.
Sources: GBIF (CC BY 4.0) and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.
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