Korean Rock Fern (Polystichum tsus-simense)

Korean Rock Fern

Polystichum tsus-simense

Its fronds unfurl like delicate green lace, enduring shade with quiet grace. Evergreen fern; common name: Korean Rock Fern.

Partial sun
2–3/week
Beginner
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Plant Needs

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Sunlight Thrives in bright indirect light or filtered shade; avoid direct midday sun which can scorch fronds
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Watering Keep soil consistently moist but not waterlogged; avoid allowing the root ball to dry out completely
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Temperature Prefers cool to temperate conditions; protect from frost below 0°C to prevent frond damage
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Characteristics

  • Fronds: Arching, pinnately compound, glossy dark green leaflets with serrated margins
  • Rhizome: Short, scaly underground stem anchoring the clump
  • Sori: Clustered on undersides of mature fronds, covered by brown rounded indusia
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Care Guide

Watering

Keep soil evenly moist; mist fronds 2–3 times weekly to boost humidity

Fertilization

Diluted organic feed once monthly. Use nitrogen-rich diluted feed to support frond growth; avoid over-fertilizing which can burn roots

Composted banana peel tea:Soak fully composted banana peels in water for 24 hours, dilute 1:20 for root drench; avoid raw peels to prevent pest infestations
Pruning
  • Remove brown, dead fronds at the base to improve airflow and tidy the clump
  • Trim damaged frond tips to maintain a neat appearance
  • Divide overcrowded clumps in early spring for propagation and healthier growth
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Toxicity

Warning: this plant may be toxic.

Pets & Humans

Pets: ASPCA confirmed non-toxic to cats; no reported toxicity symptoms

Humans: Non-toxic to humans; no known adverse health effects from contact or ingestion

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Garden Uses & Culture

Culture: N/A

Usage: Ornamental shade plant for rock gardens, container planters, or indoor terrariums