Does it need full sun?

No, it prefers partial to full shade.

Can I grow it indoors?

It is difficult to keep happy indoors due to its high humidity requirements.

Plant guide

Black spleenwort.

Asplenium adiantum-nigrum

Pronounced as-PLEE-nee-um ad-ee-AN-tum NY-grum

Also known as Black Spleenwort

The black spleenwort is a lovely, hardy fern that thrives in rocky crevices. It's a classic choice if you want to add some delicate, dark-stemmed texture to your collection. You'll find it's quite resilient once it settles into its spot.

Another photo of Black spleenwort — Photo by Patrick Le Mao (CC0) via gbif

At a glance

Care level: Moderate
Plant type: Fern
Light: Partial shade to full shade
Indoor light: Medium light
Water: Every 3 to 7 days
Mature size: 12 to 18 inches
Growth rate: Slow
Hardiness: USDA 7 to 9
Bloom time: None, this is a fern.

Care

Keep the soil consistently moist but never soggy to mimic its natural rocky habitat. Watch for crispy frond tips, which often signal that the air is too dry for this fern. Ensure it has excellent drainage to keep the roots happy.

Watering: Water whenever the top inch of soil feels slightly dry to the touch.
Feeding: Use a balanced liquid fertilizer diluted to half strength during the growing season.
Pruning: Trim away any yellow or brown fronds at the base to keep the plant looking tidy.
Repotting: Move to a slightly larger pot only when the roots have filled the current container.
Soil: Well draining, rocky, or gritty potting mix
Soil pH: Neutral to slightly alkaline
Temperature: -10 to 25°C
Humidity: 60 to 90%
Drought tolerance: Moderate
Lifespan: Perennial, typically 5 to 10 years.
Deer and rabbits: High

Signs it needs repotting

Roots circling the bottom of the pot
Water running straight through without soaking in

Safety

People: There are no reports of toxicity for this species.
Children: Keep away from small children to prevent accidental ingestion of fronds or soil.
Contact allergens: The spores may cause mild irritation if inhaled in large quantities during cleaning.
Airborne allergens: Spore release can trigger mild respiratory sensitivity in susceptible individuals.
Edibility: This plant is not considered edible.

How to identify it

Dark, shiny, blackish leaf stalks
Triangular to lance shaped fronds
Deeply divided, leathery leaflets
Small brown spore clusters underneath

Height: 0.1 to 0.4m
Spread: 0.15 to 0.3m
Leaves: dark green, glossy, evergreen
Flowers: 0cm

Problems to watch for

Scale insects · Small sap sucking insects that appear as brown bumps on the fronds.
Root rot · Occurs when the soil stays too wet for too long.

By symptom

Plant problems by symptom

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Growing it

Propagation: division, spores
When to plant: spring, early autumn
Overwintering: Keep the plant sheltered from harsh, drying winds. Ensure the crown stays dry to prevent rot during cold, wet periods.
In containers: It grows well in shallow terracotta pots with excellent drainage, provided humidity is managed.

Division

1. Carefully lift the plant in spring.
2. Gently tease the rhizomes apart.
3. Replant in fresh, gritty soil.

Pair with other rock-loving ferns to create a naturalistic, low-maintenance crevice garden.

Grows well with

Common Polypody · They share similar light and moisture needs in rock garden settings.
Wall Rue · These ferns naturally occur together in limestone wall crevices.

Similar species

Maidenhair Fern · It shares a similar delicate look but prefers consistently wetter soil.

Science

Family: Aspleniaceae
Genus: Asplenium
Order: Polypodiales
Class: Polypodiopsida
Native range: Europe, parts of Africa, and Western Asia.
Conservation: It is not currently listed as endangered.

It thrives in rocky crevices and walls where it can access moisture while maintaining excellent drainage.

Value to wildlife: provides shelter for small invertebrates
Uses: rock gardens, wall crevices, shaded borders

Through the year

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Flowering

Fruiting

Foliage

Ecological indicators

Salinity: 1/9
Soil reaction: 6/9
Light: 3/9
Temperature: 5/9
Moisture: 5/9
Nutrients: 3/9

Taxonomy resolved against GBIF.

Questions people ask

Does it need full sun?: No, it prefers partial to full shade.
Can I grow it indoors?: It is difficult to keep happy indoors due to its high humidity requirements.

Where the name comes from

The genus name Asplenium comes from the Greek for spleen, as it was historically used to treat spleen ailments, while adiantum-nigrum refers to its dark, maidenhair-like appearance.

Good to know

It is commonly called the black spleenwort.
The name refers to the dark, shiny stalks of the fronds.
It often grows in the mortar of old stone walls.

Also in

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This guide was generated with AI on October 19, 2026 and checked against GBIF taxonomy. It is general information, not horticultural or veterinary advice. Read about how we build these guides.