Blue star fern

Blue star fern: how do you recognise it?

Growth habit

Evergreen, epiphytic fern about 60 cm tall and wide, with arching fronds.

Fronds

Deeply cut (pinnate), up to about 60 cm long, blue-green and leathery, with wavy lobes.

Rhizome

Thick and creeping, covered in golden-brown, furry scales. It grows on the surface of the compost and must not be buried.

Spore clusters

Two rows of round, golden-yellow spore clusters under the fronds. There are no flowers.

Roots

Fine and shallow, mostly under the rhizome: it needs a wide, shallow pot.

Plants: March–April

Why grow it?

• Striking, deeply cut blue-green foliage that gives a room a tropical feel.
• Tolerates drier room air than most ferns.
• The furry, golden-brown rhizome creeps over the pot rim and is a feature in its own right.
• Evergreen and fairly easy, as long as the rhizome does not stay too wet.
• Lovely in a wide, shallow pot, on a plant stand or in a hanging pot.

Blue star fern: where does it grow best?

• Bright light to light half shade without direct sun, for example near an east- or north-facing window. Direct midday sun scorches the fronds.
• A very airy, humus-rich mix: potting compost with a third of fine bark and perlite, or special fern compost; slightly acid to neutral.
• Warm: 15–25 °C and never below 10 °C.
• Normal room air is enough; a tray of clay pebbles is a bonus. Keep it away from draughts and radiators.

Light

Bright, out of direct sun or low light

Potting soil

Multi-purpose compost or airy, humus-rich compost

Acidity

Acid or neutral

Watering

Moderately

Size

0.6 m tall, 0.6 m wide

Temperature

Minimum 10 °C

Goes well with

• Cretan brake (Pteris): Another fern that likes the same light shade.
• Philodendron: Large, glossy leaves as a contrast to the fine, blue-green foliage.
• Peperomia: A compact foliage plant for the same bright spot.
• Orchids: Enjoy the same bright spot without sun and the same airy mix.

Blue star fern: when and how to plant it?

Plant in March–April.

1. Repot in March–April and no more often than every 2–3 years: it likes to be a little snug.
2. Choose a wide, shallow pot with drainage holes, because the rhizome spreads sideways.
3. Mix airy potting compost with a third of fine bark and perlite so that water drains well.
4. Lay the rhizome on top of the compost and do not cover it; just fill in around the roots and firm lightly.
5. Water lightly and then let the top layer dry out a little. Keep it out of strong sun for the first few weeks.

Care

Water

Let the top 2–3 cm dry out between waterings. Water along the edge of the pot and not onto the rhizome, which rots if it stays wet. In summer usually weekly, in winter every 10–14 days.

Feeding

From April to September every 4 weeks, a quarter to half dose of liquid feed; ferns are sensitive to salts. Not in winter.

Humidity

It tolerates drier air than most ferns, but looks better at 50 % or more. A tray of damp clay pebbles or an occasional mist helps.

Rhizome

Let the rhizome hang over the rim of the pot and do not cover it with compost. Do not cut through it: the plant grows from the tips.

Light

Turn the pot now and then for even growth and do not put it in strong sun.

Tip: Lay the rhizome on top of the compost and do not cover it. Let the top layer dry out slightly and use a wide, shallow pot: it tolerates drier air than most ferns.

Blue star fern: when to prune it?

When: Real pruning is not needed. Cut off dead or yellow fronds all year round, preferably in spring.

How:

• Cut brown, yellow or damaged fronds off right at the base with clean scissors.
• Leave green, healthy fronds in place; new fronds grow from the tips of the rhizome.
• Do not cut through the rhizome itself.

Caution: Do not cut off the golden-brown rhizome: the plant grows from the tips and recovers poorly from a cut.

Pruning calendar and basic rules

Propagation

Division

In March–April: cut the rhizome with a clean knife into pieces of at least 5–10 cm with 2–3 fronds and some roots. Lay each piece on moist, airy compost, pin it down with a hairpin if needed and keep it warm, bright and moist.

Spores

Possible but slow: sprinkle spores on moist, sterile compost under a clear lid at 20–22 °C and in the light. It takes months before little plants appear.

Blue star fern: how does it get through the winter?

• Not hardy: the minimum temperature is 10 °C. It overwinters indoors.
• Keep it bright, at 15–20 °C, away from radiators and draughts.
• Water less: the top layer may dry out further, roughly every 10–14 days. The rhizome must not stay wet.
• Do not feed from October to February inclusive.

Diseases and pests

• Brown frond tips or edges: Air that is too dry, hard water or compost that has dried out. Use rainwater, water more regularly and raise the humidity.
• Rotting rhizome: A soft, dark rhizome caused by compost that is too wet or because it was buried. Cut away the affected part, let it dry and reposition it higher in a more open mix.
• Yellow fronds: Too wet, too dark or salt build-up. Let the top layer dry out, flush the compost through and move it somewhere brighter.
• Scale insects and mealybugs: Brown shields or white fluffy patches on the stalks and rhizome. Wipe them off with a cotton bud dipped in soapy water and repeat weekly; ferns are sensitive to many sprays.

Through the year

• January: Rest: bright, 15–20 °C, sparing with water.
• February: Rest. Keep an eye on dry air from heating.
• March: Repot and divide. Cut off dead fronds.
• April: Repotting still possible. Start feeding (quarter to half dose).
• May: Growth. Water regularly, shade from strong sun.
• June: Growth. Feed every 4 weeks.
• July: Growth. Watch for drying out in hot weather.
• August: Growth. Feed every 4 weeks.
• September: Last feed. Check for pests.
• October: Water less. Stop feeding.
• November: Rest: bright and sparing with water.
• December: Rest. Keep away from radiators.

Did you know?

• In the wild it grows as an epiphyte on tree trunks and branches, where it feeds on plant debris.
• The species name aureum means ‘golden’, after the golden colour of the spore clusters and the scales on the rhizome.
• It used to be called Polypodium aureum; it was later placed in a genus of its own, Phlebodium.