Giant Orchid (Himantoglossum robertianum)

Giant Orchid

Himantoglossum robertianum

Its large, insect-mimicking blooms blend wild elegance with evolutionary ingenuity. Terrestrial perennial orchid; common name: Giant Orchid.

Partial sun
1–2/week
Moderate
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Plant Needs

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Sunlight Bright indirect to partial direct sunlight; avoid intense midday summer sun to prevent leaf scorch
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Watering Water thoroughly when the top 2 cm of substrate is dry; ensure excellent drainage to avoid root rot
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Temperature Thrives in cool to temperate temperatures; tolerates brief light frosts during its winter dormant period
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Characteristics

  • Leaf: Basal rosette of 3–6 oblong, fleshy, pale green leaves, up to 30 cm long
  • Flower: Dense spike of 10–20 large, greenish-brown blooms with a long, tongue-like labellum mimicking a fly
  • Stem: Erect, sturdy green stem with sheathing bracts below the flower spike
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Care Guide

Watering

Keep substrate evenly moist during active growth and blooming

Fertilization

Diluted balanced orchid fertilizer every 2 weeks. Use a fertilizer formulated for terrestrial orchids to avoid nutrient burn

Eggshell powder top-dress:Grind clean, dried eggshells to a fine powder; dust lightly on the soil surface to boost calcium levels and maintain alkaline pH
Pruning
  • Remove spent flower spikes after blooming to redirect energy to root and leaf growth
  • Trim yellowing basal leaves during the winter dormant period to reduce fungal risk
  • Divide overcrowded clumps in early spring before new growth emerges to maintain plant health
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Toxicity

Warning: this plant may be toxic.

Pets & Humans

Pets: ASPCA: No documented toxicity to cats

Humans: No known toxic effects on humans

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Garden Uses & Culture

Culture: N/A

Usage: Ornamental wild orchid for native plant gardens and specialized orchid collections