Japanese holly fern

Japanese holly fern: how do you recognise it?

Habit

Clump about 60 cm tall and wide, with slightly arching fronds rising from a central crown.

Fronds

Divided once, with glossy, leathery leaflets that are sickle-shaped and sometimes slightly toothed; dark green and evergreen.

Stems

Sturdy, with brown scales at the base.

Spores

Ferns do not flower; the round spore clusters are scattered over the underside of the leaflets.

Roots

Short, upright rhizome with a dense root system.

Plants: April–May and September · Pruning: March–April

Why grow it?

• Evergreen: the glossy leaves stay fresh and attractive all winter.
• Bold, glossy foliage that contrasts with finer ferns and other shade plants.
• Copes with dry air and a little drought better than many other ferns, also in a pot.
• Versatile: in a sheltered garden, in a pot on the patio or indoors as a houseplant.
• Little work: just cut away the old fronds in spring.

Japanese holly fern: where does it grow best?

• Part shade or shade; strong sun scorches the leaves.
• Humus-rich, well-drained soil: sand, loam or clay, acid to chalky.
• Normally moist; rather drier in winter, as cold and wet feet together are fatal.
• Sheltered from cold winds, for instance against a wall or under evergreen shrubs; allow 50–60 cm per plant.

Light

Partial shade and shade

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Normal

Size

0.6 m tall, 0.6 m wide

Hardiness

Half hardy (to -10 °C): protect it in harsh winters

Goes well with

• Hellebore: Evergreen and flowering in winter, also in part shade.
• Barrenwort: A low ground cover with dainty spring flowers.
• Hosta: Broad, soft leaves in summer beside the glossy, stiff fern fronds.
• Snowdrop: White bells in February among the evergreen fronds.
• Japanese forest grass: An arching grass that adds softness beside the sturdy fronds.

Japanese holly fern: when and how to plant it?

Plant in April–May and September.

1. Plant in April–May, so it is well established before its first winter; September is also possible, but then definitely in a sheltered spot.
2. Dig a generous hole and mix in leaf mould; on heavy soil, also add some coarse sand for drainage.
3. Set the plant at the same depth as it was in the pot, with the crown just above the soil, no deeper.
4. Keep 50–60 cm between it and other plants.
5. Water in well straight away and then regularly until established.
6. In a pot: choose a roomy pot with a drainage hole and humus-rich compost with some sand or perlite.

Care

Watering

In the garden, in dry spells. In a pot, regularly, as soon as the top few centimetres are dry; indoors, a little less in winter.

Feeding

In the garden, a layer of leaf mould in spring. In a pot, a little liquid feed at half strength every month from April to August.

Old fronds

In March–April, cut away damaged or discoloured fronds as soon as the new ones start growing.

As a houseplant

Place it in a light spot out of direct sun, ideally in a cool room; it tolerates drier air better than many other ferns.

Repotting

Repot every two to three years in spring into a slightly larger pot.

Tip: Plant it against a north- or east-facing wall, or under evergreen shrubs: there it is sheltered from cold winds and the leaves stay attractive all winter. If it is in a pot, simply bring it indoors during severe frost.

Japanese holly fern: when to prune it?

Pruning months: March–April.

When: In March–April, as soon as the new fronds begin to unfurl. As it is evergreen, only cut away what looks untidy.

How:

• Cut old, brown or frost-damaged fronds off at the base.
• Leave healthy green fronds: they stay attractive for a long time yet.
• Watch out for the young, coiled fronds in the centre.

Caution: Do not cut the fronds off in autumn: they protect the crown from frost.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Spores

In summer, let a ripe frond drop its spores onto paper and sow them on moist, sterile compost under glass or plastic, in a light spot out of the sun. They germinate fairly readily, but it takes months to get a small plant.

Division

Older plants with several crowns can be divided carefully in April; replant the pieces straight away at the same depth.

Japanese holly fern: how does it get through the winter?

Hardy to −10 °C: protect in harsh winters.

• Moderately hardy, to about −10 °C: in mild Belgian winters it survives in a sheltered spot, but severe frost can kill it.
• In November, spread a thick layer of leaves or straw around the base and over the crown, and leave the old fronds standing.
• In a pot: in severe frost, bring it into a cool, light, frost-free place, such as an unheated room or conservatory, and water sparingly.
• As a houseplant: keep it cool, light and a little drier in winter.

Diseases and pests

• Frost damage: Brown, limp fronds after a severe winter. Cut them off in spring; the crown often grows again.
• Scale insects: Brown, firmly attached bumps along the stems and veins, mainly indoors. Gently rub them off. The round spore clusters on the underside of the fronds are not scale insects.
• Root rot: Yellow fronds and a rotting crown caused by wet feet, especially in winter. Ensure good drainage and water less in a pot.
• Scorched leaves: Yellow or brown patches caused by strong sun. Move it to a shadier spot.

Through the year

• January: Give extra protection in severe frost. Keep pots indoors cool and light.
• March: Cut away damaged fronds. Remove the winter mulch.
• April: Plant. Repot. Cut away old fronds; the new ones unfurl.
• May: Plant. Feed plants in pots.
• July: Water in dry spells. Collect spores.
• August: Water in dry spells.
• September: Plant in a sheltered spot.
• November: Spread leaves or straw around the base. Bring pots indoors in severe frost.
• December: Evergreen leaves. Keep pots indoors in frosty weather.

Did you know?

• The species name falcatum means ‘sickle-shaped’ and refers to the shape of the leaflets.
• It has long been grown as a houseplant, because it copes with dry indoor air better than many other ferns.
• In mild coastal areas of western Europe it has naturalised here and there, including on old walls.