Ornamental · Dryopteridaceae
Christmas Fern
Polystichum acrostichoides
Give it shade and well-drained soil, and the Christmas fern holds its green fronds straight through winter.
Partial shade
Every 5–10 days
USDA 3–9
12–35 in · 30–90 cm
Overview
The Christmas fern is one of the easiest native ferns to grow, and one of the few that stays green all winter. It forms a tidy, non-spreading clump of leathery, dark green fronds, and the small leaflets are shaped a bit like Christmas stockings, which is where the name comes from. It belongs to the wood fern family and grows wild across much of the eastern woodlands.
What sets this fern apart is its toughness. It shrugs off cold down to -40°F (-40°C), handles deep shade, and copes with the dry, rocky, root-filled ground under trees where little else will grow. New fiddleheads unfurl in spring while last year's fronds are often still standing, so the plant never really goes bare.
It asks for almost nothing once it's settled. Give it shade, soil that drains, and a little patience while the clump fills out, and it will hold a quiet, evergreen presence in the garden for years. Gardeners often use it to anchor a shady slope or carpet a woodland bed.
Care
The short version: plant it in part to full shade in rich, well-drained soil, keep it evenly moist while it establishes, and then mostly leave it be.
Light
This is a shade plant at heart. It does best in partial to full shade and will take deep shade in stride, which makes it a rare fit for the darker corners of the garden. A little morning sun is fine, but harsh afternoon light scorches the fronds.
Water
Keep the soil evenly moist while the fern establishes, watering every 5 to 10 days when rain is short. Once the roots take hold it handles brief dry spells without complaint, so you can ease off. What it won't forgive is standing water.
Soil
Plant in rich, well-drained loam with plenty of organic matter, though this fern also copes with sandy or shallow rocky ground. It likes things a touch acidic, around a pH of 5.0 to 6.5. Good drainage matters more than anything, since wet feet invite crown rot.
Temperature
Few garden plants are this hardy. It survives from -40°F to 86°F (-40°C to 30°C), covering USDA zones 3 through 9. Winter cold is no threat, and the fronds keep their color right through it.
Humidity
Ordinary outdoor humidity suits it fine, so there's no number to aim for. Steady soil moisture matters far more to this fern than the moisture in the air.
Feeding
This fern barely needs feeding. A light topdressing of compost or a balanced slow-release fertilizer in spring is plenty, and many gardeners skip even that. Overfeeding does more harm than good.
Pruning
Pruning is a once-a-year job. In late winter or early spring, before the new fiddleheads push up, cut away the old, tattered, or winter-damaged fronds so the fresh growth comes in clean.
Size & spacing
Each clump grows 12 to 35 inches (30 to 90 cm) tall with a matching spread. Give plants about that much room apart so the fronds have space to arch out, and the non-spreading clumps will hold their shape without crowding.
When to plant
There's no flowering season to chase with a fern, and no harvest. Plant it out in spring as the soil warms and the fiddleheads start to rise, and it settles in over the next season or two.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: spring
Hardiness
USDA hardiness zones: 3–9
Temperature: down to -40°C
Troubleshooting
This fern stays healthy with little fuss, so trouble is rare and usually traces back to soggy soil or a hungry pest. Learn the two signs below and you can catch either one early. Match what you see, then act before it spreads.
Wilting fronds and a soft, blackened crown
This is crown rot, and it sets in when the soil stays soggy, especially over a wet winter. Cut back on water and improve the drainage, then dig out and discard any soft, darkened tissue at the base. Replanting the rhizome at a slight angle helps water run off the crown instead of pooling on it.
Fix:
- Improve drainage and reduce watering
- Plant the rhizome at an angle to shed water from the crown
- Remove and discard affected tissue
Ragged, chewed leaflets and stripped fronds
Ragged margins and bare stems point to the Florida fern caterpillar, which feeds after dark and can clear a frond fast. Check the plant by flashlight at night and pick the caterpillars off by hand. A heavy infestation may call for an appropriate insecticide, but watching the foliage and catching them early usually settles it.
Fix:
- Hand-pick caterpillars
- Treat with an appropriate insecticide if infestation is heavy
Toxicity
Good news for households with pets and children: the Christmas fern is safe all around. The ASPCA lists it as non-toxic to cats, dogs, and horses, and there's no poison in the fronds to worry about for other animals or people.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
The ASPCA lists this fern as non-toxic to cats, so a curious nibble is nothing to worry about. As with any plant, a mouthful of fronds might bring on a little stomach upset, but there's no poison at work.
Dogs None
Dogs can be around this fern without any risk, since it carries no toxins. A dog that chews a few fronds is safe, though a big helping of rough greenery could pass through messily.
Horses None
Confirmed non-toxic to horses, so a grazing horse is in no danger here. The fronds are simply not poisonous.
Rabbits Safe
Rabbits can browse the fronds without harm. There's no toxin in this fern to trouble them.
Livestock Safe
Cattle, goats, and sheep can graze near this fern safely, as it holds nothing poisonous. It won't cause the kind of trouble that some pasture ferns do.
Birds Safe
Pet and backyard birds are fine around this fern. Nothing in the fronds will hurt them.
People Safe
The plant poses no poisoning risk to people, including children who might handle the fronds. It isn't grown to eat, so there's no reason to make a meal of it, but a touch or a taste does no harm.
Varieties
Unlike many garden plants, this fern is grown almost entirely as the wild species, with named cultivars hard to come by. There's really just the one to know.
Polystichum acrostichoides (species)
Almost always grown as the straight species, it carries leathery, evergreen, dark green fronds whose stocking-shaped leaflets hold their color through winter into the Christmas season, and named cultivars are rare.
How to propagate
Making more Christmas ferns is straightforward, whether you split a clump you already have or take the slower path of growing from spores.
DivisionEasy
Spring · 1 to 2 growing seasons
The simplest way to make more is to divide an established clump in spring, splitting the crown and replanting the pieces, which take a season or two to settle in and fill out. You can also raise it from spores carried on the upper third of the fertile fronds, though that route is much slower.
Myths
The Christmas fern is named for blooming or fruiting at Christmas.
Ferns never flower or set berries, so the name has nothing to do with a winter bloom. It comes from the leathery fronds that stay green through winter into the Christmas season, along with leaflets shaped like little Christmas stockings.