Hard shield fern

Hard shield fern: how do you recognise it?

Habit

Shuttlecock-shaped clump 60–90 cm tall and about 70 cm wide, from one or a few crowns.

Fronds

Lance-shaped, narrowing towards the base, twice divided, stiff and leathery; the pinnules are attached almost without a stalk.

Colour

Glossy dark green all year round. The young croziers are covered in pale brown scales.

Edge

Finely toothed, with a prickly tip on each pinnule.

Spores

Round spore clusters in rows under the frond, with a round membrane; ferns do not flower.

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

Why grow it?

• Evergreen: stiff, glossy fronds that look good in winter too.
• One of the best ferns for chalky soil in the shade.
• Native and at home in a natural woodland garden or on a shady slope.
• A regular shuttlecock of fronds that gives structure to a shade border.
• Does not spread: it stays a neat clump in its place.
• Little work: cutting off the old fronds once a year is enough.

Hard shield fern: where does it grow best?

• Partial shade to shade; no fierce midday sun.
• Humus-rich, well-drained soil: sand, loam or clay, neutral to chalky. A shady slope is ideal.
• Normally moist: cool and moisture-retentive, but not waterlogged in winter.
• Sheltered from drying winds, which turn the evergreen fronds brown.
• Plant 60–70 cm apart, or in a group of three at 60 cm.

Light

Partial shade and shade

Soil type

Sand, loam or clay

Acidity

Neutral or chalky

Moisture

Normal

Size

0.7 m tall, 0.7 m wide

Hardiness

Hardy (to -25 °C)

Goes well with

• Hart’s-tongue fern: Another native, evergreen fern for chalky shade, with glossy, undivided fronds.
• Stinking hellebore: A native, evergreen perennial with pale green flowers in winter, also on chalk.
• Sweet woodruff: A low, fresh green ground cover with small white flowers in May.
• Snowdrop: White bells in February beside the evergreen fern fronds.
• Hosta: Large, broad leaves as a calm contrast to the fine, stiff fern fronds.

Hard shield fern: when and how to plant it?

Plant in March–May and September–October.

1. Plant from March to May or in September–October, when the soil is neither frozen nor too dry.
2. Loosen the soil and work in leaf mould; in heavy clay also add some coarse sand or grit.
3. Dig a hole twice as wide as the pot and set the plant at the same depth as before: the crown belongs at the surface, not below it.
4. On a slope, set it slightly tilted so rainwater does not sit in the crown.
5. Leave 60–70 cm between plants and firm the soil well.
6. Water thoroughly straight away and keep the soil moist for the first few weeks. Spread a thin layer of leaf mould around the plant, not over the crown.

Care

Water

In the first year, water weekly in dry spells. After that only in long dry periods.

Feeding

Little needed: in April a layer of leaf mould or well-rotted compost. No chemical fertiliser.

Mulching

Leave fallen tree leaves around the clump, but remove them from the crown.

Old fronds

In March cut off old and damaged fronds, before the new croziers unfurl.

In a pot

A roomy pot with humus-rich, free-draining compost. Do not let it dry out, and in winter do not leave it standing in a saucer of water.

Tip: Plant it on a shady slope or in well-drained, chalky soil with plenty of leaf mould: there the fronds stay glossy green all winter. Only cut off the old fronds in March.

Hard shield fern: when to prune it?

Pruning months: March.

When: In March, before the new croziers unfurl. Otherwise this fern needs no pruning.

How:

• Cut the old fronds off just above the crown, even if they are still green: the new fronds will then show off well.
• If you want to keep the evergreen fronds longer, just remove the brown and damaged ones.
• Work carefully around the scaly croziers in the centre.
• Wear gloves: the prickly tips of the fronds are a little sharp.

Caution: Do not wait too long: once the new fronds are out, it is easy to cut them off by mistake.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Spores

In late summer lay a ripe frond on a sheet of paper and sow the released spores on sterile, moist compost under glass. Small ferns appear after a few months; it takes a few years to get a sizeable plant.

Division

Older plants with several crowns can be divided with a sharp spade in March–April, each piece with a crown and roots. Replant at once and water well.

Hard shield fern: how does it get through the winter?

Hardy to −25 °C.

• Hardy to about −25 °C: no protection is needed in Belgian gardens.
• The fronds stay green and glossy all winter; only hard frost with drying wind browns them a little.
• Leave the old fronds until March: they decorate the winter garden and protect the crown.
• In a pot: stand it against a sheltered wall and wrap it in hessian during severe frost.

Diseases and pests

• Crown rot: The crown turns brown and soft in wet, compacted soil. Plant in a well-drained spot or on a slope, and remove wet leaves from the crown.
• Brown fronds: Dry, brown frond edges from drying wind, fierce sun or drought. Water, mulch and provide shelter.
• Late frost: The young croziers can freeze in April–May. Cover with fleece if frost is forecast; the plant usually regrows.
• Vine weevil: Mainly in pots, the grubs eat the roots and the plant wilts for no obvious reason. Check the root ball and use nematodes against the grubs in late summer.

Through the year

• March: Cut off the old fronds. Spread leaf mould.
• April: The scaly croziers unfurl. Plant. Watch out for late frost.
• May: Plant. Water in dry spells.
• June: Water in dry spells.
• July: Water in dry spells.
• August: Collect ripe spores.
• September: Plant. Collect ripe spores.
• October: Plant. Remove fallen leaves from the crown.
• December: The glossy, evergreen fronds decorate the winter garden.

Did you know?

• ‘Aculeatum’ means ‘prickly’: each pinnule ends in a fine, prickly tip.
• Polystichum means ‘many rows’, after the rows of spore clusters under the frond.
• You can tell it from its relative the soft shield fern because its pinnules are stiffer and attached to the midrib almost without a stalk.