Ornamental · Aspleniaceae
Hart's Tongue Fern
Asplenium scolopendrium
Give it deep shade, steady moisture, and a little lime, and this glossy strap-leaved fern will reward you by holding its green right through winter.
Full shade
Every 5–10 days
USDA 5–9
12–18 in · 30–46 cm
Overview
If you are just starting out, this is a lovely, forgiving fern to fall for. What makes it special is what it skips: its fronds never break into the lacy, feathery shape most people expect. Instead they roll open as long, glossy, undivided straps of bright green, rising from a snug central crown into a neat little shuttlecock of leaves.
It comes from the spleenwort family and grows wild across Europe, tucked against shaded limestone walls, rocky banks, and cave mouths. That home life is a friendly hint about what it craves from you: cool shade, a sweet alkaline soil, and steady moisture, never a soggy bath. Settle it in the right nook and it stays evergreen, keeping its fronds even through a hard winter.
Think of it as a calm, unhurried companion rather than a fast gap-filler. Give it shelter and shade and it hands back a bold, almost reptilian texture that brightens a dim corner under trees or beside a north wall. You've got this.
Care
The short version: it will be happy with full to partial shade, soil kept evenly moist yet sharply drained, and a sweet alkaline mix with a touch of lime, plus a little extra humidity like the shaded rock it came from.
Light
This one is a shade lover, plain and simple, so you can relax about that dim corner. It wants full to partial shade, the sort of dappled or deep cover it would find under trees or against a north wall. Just keep it clear of hot afternoon sun, which will scorch the fronds.
Water
Aim to keep the soil evenly moist but never waterlogged, giving it a drink every 5 to 10 days and a touch more through a dry stretch or its first season in the ground. The one thing to watch is drainage, because it dislikes standing water as much as drought, so moist soil that drains freely is exactly the sweet spot you're after.
Soil
Set it into humus-rich, well-drained soil that leans alkaline, ideally a pH between 6.5 and 8.0. Happily, it is one of the rare ferns that truly loves lime, so a chalky or limestone-rich mix suits it beautifully where fussier plants would sulk.
Temperature
It is wonderfully cold-hardy, shrugging off winter lows down to -20°F (-29°C) and summer warmth up to about 75°F (24°C). Those wide limits are exactly why it stays evergreen across zones 5 to 9 rather than tucking itself underground.
Humidity
Since it grew up on shaded rock and cave mouths, it enjoys air on the damp side, around 50% to 80%. In a dry room or an exposed bed the frond tips may brown, so group it with leafy neighbors or set it where the air sits calm and moist.
Feeding
Good news for anyone worried about feeding schedules: ferns are light feeders, so a soft touch is best. One drink of diluted, balanced liquid fertilizer in spring is plenty, and going heavier does more harm than good.
Pruning
There is very little fuss here, which makes it a joy. Pluck off any dead or damaged fronds as you notice them, and cut back the tatty, winter-burned old fronds in late winter, right before the new croziers begin to unfurl.
Repotting
A potted plant only needs a fresh home every 2 to 3 years, or a little sooner if roots poke through the drainage holes, the crown looks crowded, or water rushes straight through. Move it up into a slightly bigger pot with fresh, lime-rich, gritty mix and it will settle right in.
Size & spacing
It stays compact and grows slowly, reaching about 12 to 18 inches (30 to 46 cm) tall and roughly as wide. Leave each plant 12 to 18 inches (30 to 46 cm) of elbow room so the crowns can open into their full rosette of fronds.
When to plant
This fern is tough and never in a rush, so there is no pressure. Sow ripe spores indoors in spring if you'd like to raise your own, and move young plants outside in spring once the hard frost has gone. It stays evergreen in zones 5 through 9, which means once it settles it keeps its fronds all year instead of vanishing to the ground.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: Sow ripe spores indoors in spring at about 15°C (60°F)
- Plant: Spring, after the danger of hard frost has passed
Hardiness
USDA hardiness zones: 5–9
Temperature: down to -29°C
Troubleshooting
Take comfort in this: almost every hiccup with this fern comes down to water and light, not creepy pests. Wet roots and harsh sun are behind nearly all of it, and both are easy to put right. Find the picture that matches yours below, then gently ease the conditions back before things spread.
Fronds flopping while the roots go soft and dark
Take heart, because this is root rot from soil that stayed too soggy, not some illness spreading through your garden. Slip the plant out and the roots will feel soft and smell sour instead of firm and pale. Trim off the bad parts, sort out the drainage, and settle it into a gritty, lime-rich mix, and the crown can still pull through.
Fix:
- Improve drainage immediately
- Reduce watering frequency
- Repot into a gritty, well-drained, lime-rich mix and trim away rotted roots
Crisp brown tips and edges along the fronds
Those dry, crispy edges are sun scorch, often with a bit of parched air or soil that got too thirsty behind them. You will notice it worst on the side that faces the sun, while the shaded fronds stay a happy green. Shift the plant to a shadier spot, lift the humidity around it, and keep the soil gently moist, and the new growth will come in clean.
Fix:
- Move to a shadier spot
- Raise humidity around the plant
- Keep soil evenly moist
Older fronds fraying and browning through the cold months
Please don't worry, because this is just winter burn on the oldest outer fronds, the work of cold and drying wind on an evergreen. It can look scruffy, yet the heart of the plant is safe and ready to push fresh growth when spring arrives. Snip the ragged fronds away in late winter, before the little croziers begin to uncurl.
Fix:
- Cut back damaged fronds in late winter before new croziers unfurl
Toxicity
Here is a comforting thought for a shady spot shared with pets and little ones: this fern is not known to be toxic. Like other true ferns it carries no documented toxin, though this exact species hasn't been formally evaluated, so treat it as low-risk rather than certified safe. The one thing worth a gentle heads-up is physical, since the fronds and spores can scratch or irritate sensitive skin, so simply wash your hands after handling it.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
You can relax with a cat in the house, since this fern poses no toxic threat. If a curious kitty takes a taste, expect nothing worse than the little tummy upset any leafy nibble might bring.
Dogs None
Your dog is in safe company here, with nothing poisonous to worry about. A chewed frond might bring on a bit of drool or a passing lack of appetite from the roughage, and that is all.
Horses None
Horses are perfectly fine grazing nearby, so there is no need to fence this one off. A true fern like this holds no toxin that would ever trouble them.
Rabbits None
A rabbit can nibble a frond and come to no harm at all. Just let it be one small part of a mixed diet rather than the whole dinner.
Livestock None
Cattle, goats, and sheep have nothing to fear from this fern and can rest easy sharing a shaded paddock with it.
Birds None
Birds are safe and sound around the plant, whether they settle in among the fronds or give one a curious peck.
People None
It is a gentle plant to keep with children, safe to handle and grow beside them. The one small thing to remember is that the fronds and spores can scratch or bother sensitive skin, so a quick wash of the hands after pruning keeps everyone comfortable.
Fronds and spores may cause mild mechanical irritation in sensitive individuals; wash hands after handling.
Varieties
Past the plain species, gardeners cherish a small handful of selections for the way their fronds twist, ripple, and flare. These are the friendly forms worth getting to know.
'Crispum'
A much-loved garden form whose strap-shaped fronds carry margins frilled and crimped into tight, pretty waves.
'Undulatum'
You'll know it by the way each blade ripples with bold, wavy edges from base to tip.
'Angustatum'
This gentle selection wears slimmer, more strap-like fronds than the ordinary species does.
'Sagittatum'
At the base of every frond you'll find a charming arrow- or fishtail-shaped set of lobes.
var. americanum (American hart's-tongue fern)
A scarce North American native of limestone sinkholes that is federally protected, so it is not the form you'll come across for sale.
How to propagate
There are two gentle ways to make more of this fern: split a settled clump for a quick head start, or take the slow, rewarding route from spores.
DivisionModerate
Late winter to early spring · 2-3 months for divisions; spore-grown plants take 1-2+ years to reach garden size
The kindest, easiest way to get more is division in late winter to early spring. Find a settled clump that has grown several crowns, ease it apart, and the new pieces knit in over two to three months. If you feel adventurous, you can sow ripe spores on the surface of a sterile mix and hold them at about 60°F (15°C), though be patient, since a spore-grown plant needs one to two years or more to reach garden size.
Myths
Because its fronds are undivided and strap-like, it is not a real fern.
Rest easy, because this is a true fern through and through. It reproduces by spores, tucked into tidy herringbone rows along the frond undersides, even though its leaves never break into the lacy pattern folks tend to expect.
Hart's tongue fern is endangered and against the law to grow.
You are free to grow the common European species, which is widespread and sold openly for gardens. Only the North American native variety, var. americanum, is rare and legally protected, and that is simply not the plant you'll find waiting at the nursery.