Ornamental · Dryopteridaceae
Autumn Fern
Dryopteris erythrosora
Plant it in moist shade and the autumn fern lights up the season with copper-red new fronds.
Partial shade
Every 5–7 days
USDA 5–9
18–30 in · 45–76 cm
Overview
The autumn fern is a tough, good-looking woodland fern from East Asia, grown for the copper-red color of its new fronds. Those fronds emerge bronze to orange-red in spring, then deepen to a glossy green as the year goes on. It holds its shape through the cold and stays evergreen in milder gardens, so the bed never looks bare.
It earns its keep by being easy. Give it the shade and steady moisture it likes and it asks for almost nothing else, and once settled it shrugs off dry shade and brief dry spells better than most ferns. Deer tend to leave it alone, which makes it a reliable choice for a woodland edge.
One thing to weigh before planting: it creeps along by underground rhizomes and can spread further than you bargained for. North Carolina Extension flags it as potentially weedy, so check your regional guidance before you put it in the ground.
Care
The short version: part to full shade in rich, humusy soil that stays evenly moist. Water it through the first season to get it going, tidy up old fronds in late winter, and it largely looks after itself from there.
Light
Give it part to full shade, the dappled light of a woodland floor. It will take some morning sun, but harsh afternoon light scorches the fronds unless the soil stays reliably moist.
Water
Keep the soil evenly moist, especially through the first growing season while the roots establish. Watering every 5 to 7 days suits most spots, and once settled the fern handles brief dry spells and dry shade better than most.
Soil
Plant in humus-rich, well-drained loam packed with organic matter. A slightly acidic pH of 5.0 to 6.5 suits it best, and plenty of leaf mold or compost keeps the ground moist without turning soggy.
Temperature
It is hardy and cold-tough, taking winters down to -20°F (-29°C) and warmth up to about 86°F (30°C). That range covers USDA zones 5 through 9, where it stays evergreen in the milder end.
Humidity
Average humidity around 40% to 70% keeps the fronds in good shape. Like most ferns it dislikes dry air, so a shaded, sheltered spot with moist soil does more for it than any one humidity number.
Feeding
This is a light feeder, so don't overdo it. A spring topdress of compost or leaf mold feeds it well, or use a balanced slow-release fertilizer once as growth starts.
Pruning
It barely needs cutting back. In late winter to early spring, before the new fronds unfurl, clear away any tattered, old, or winter-damaged fronds to make room for fresh growth.
Repotting
If you grow it in a container, repot every 2 to 3 years or when roots push from the drainage holes and the soil dries out fast. A crowded rhizome lifting at the surface is another sign it needs more room.
Size & spacing
Expect a clump 18 to 30 inches (45 to 76 cm) tall that spreads 24 to 35 inches (60 to 90 cm) wide. Leave room for that spread, and keep in mind it can creep further by rhizome over time.
When to plant
The autumn fern has no flowers to time and no harvest to chase, so planting is the only date that matters. Set it out in spring once the frost has passed, or in early autumn while the soil is still warm enough for roots to settle before winter.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Spring after last frost, or early autumn
Hardiness
USDA hardiness zones: 5–9
Temperature: down to -29°C
Troubleshooting
Almost every problem with this fern shows up in the fronds, and most trace back to too much sun, too much wind, or the wrong amount of water. Read what the fronds are telling you and the fix is usually simple. Match your symptom below and act before more fronds go the same way.
Fronds scorched or browning along the edges
This is sun scorch, usually paired with dry soil, and it shows up worst on the fronds catching hot afternoon light. Move the plant into deeper shade or throw some shade over it, then water deeply and mulch to hold that moisture in. Trim the worst fronds and fresh ones will push through.
Fix:
- Relocate or shade plants receiving harsh afternoon sun
- Water deeply and mulch to retain soil moisture
- Trim badly damaged fronds to encourage fresh growth
Fronds yellowing as the whole plant slips
Yellowing across the plant points to a moisture problem at the roots, in one of two directions. Soggy, waterlogged soil drowns the roots, while soil that keeps drying out starves them, so check which way yours leans before you act. Work in organic matter or move the fern off standing water for drainage, and settle into a steady routine that keeps the soil evenly moist.
Fix:
- Improve drainage by adding organic matter or relocating from standing water
- Establish a consistent watering routine to keep soil evenly moist
Fronds torn and frayed on the windward side
Strong, drying wind shreds the delicate fronds along their margins, and you'll see the tearing on the side facing the breeze with no spotting or pest signs to go with it. Snip off the battered fronds and give the plant a sheltered spot or a windbreak. A protected woodland corner keeps the foliage intact.
Fix:
- Remove damaged fronds
- Provide a sheltered planting position or windbreak
Toxicity
No source confirms this fern is poisonous, and its close relatives like Boston fern are listed as safe to pets. But no source confirms this exact species is safe either, so the honest answer is that the data isn't there yet. Until it is, keep pets, livestock, and children from chewing the fronds as a sensible precaution.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Caution
No source confirms this fern is poisonous to cats, and its close relatives like Boston fern are listed as safe. Even so, a cat that nibbles the fronds may drool or bring up a little, so it's best kept out of reach until the species is cleared.
Dogs Caution
There's no record of harm to dogs, and related shield ferns are considered non-toxic. A curious dog chewing the fronds could still get a mild upset stomach, which is reason enough to discourage the habit.
Horses Caution
No source flags this fern as dangerous to horses one way or the other. Without that confirmation, keep grazing horses away from it and watch for any drooling or dullness if some is eaten.
Rabbits Caution
Rabbits aren't covered by any toxicity entry for this fern, so its safety is simply unproven. Offer none of it until that gap is filled, and treat a chewed frond as a reason to watch the animal.
Livestock Caution
Cattle, goats, and sheep have no documented reaction to this fern, good or bad. Fence it off from grazing stock as a precaution rather than assume it's fine.
Birds Caution
Nothing on record tells us how birds handle this fern. Keep pet and backyard birds away from the fronds until a reliable source weighs in.
People Caution
No part of this fern is meant to be eaten, and no source vouches for it as food. Keep children from chewing the fronds, and don't treat it as a wild edible.
No documented toxicity, but no confirmed safety data for this exact species; discourage pets and children from chewing the fronds as a general precaution.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
Poison Control: (800) 222-1222
Canada
Poison Centres: 1-844-764-7669
Varieties
A couple of named selections turn up alongside the plain species, each with its own twist on color or habit.
'Brilliance'
Its new spring fronds come in a brighter, deeper red than the plain species and hold that color further into the season.
var. prolifica
A narrow, finely cut form that grows little plantlets along the frond stem, giving it a second way to spread on its own.
How to propagate
The autumn fern is simple to multiply, and dividing an established clump is by far the quickest way to get more.
DivisionEasy
Spring or early autumn · 1 to 2 growing seasons
Division is the easy route. In spring or early autumn, lift an established clump and pull it into sections, keeping roots and fronds on each piece, and give the divisions a season or two to settle in and fill out. You can also raise new plants from the spores ripening on the frond undersides, but that path is much slower and asks for more patience.
Myths
The autumn fern gets its name from fronds that turn coppery in fall.
The coppery bronze to orange-red color shows up on the new fronds as they unfurl in spring, then settles into a glossy deep green by summer. The name describes spring, not fall. What does turn orange-red in autumn is the ripe spores on the undersides of the fronds.
Every fern is poisonous to cats and dogs.
Plenty of true ferns in the same family, including Boston fern and sword fern, are listed as non-toxic to pets by the ASPCA. But no source confirms the status of this exact species, so the safe move is to keep pets from chewing the fronds rather than assume it follows its relatives.