Snake's Head Iris (Iris tuberosa)

Snake's Head Iris

Iris tuberosa

Its dark, velvety blooms carry a mysterious elegance. Bulbous perennial flowering plant; common names: Snake's Head Iris, Widow Iris.

Full sun
1/week
Moderate
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Plant Needs

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Sunlight Full sun to partial shade; protect from intense midday sun in warmer regions to prevent leaf scorch
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Watering Water moderately during active growth; allow the top 2–3 cm of soil to dry slightly between waterings to avoid bulb rot
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Temperature Tolerates mild frost down to 5°C; avoid prolonged temperatures above 28°C which can stress bulbs during dormancy
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Characteristics

  • Leaf: Narrow, linear grey-green basal leaves that emerge in autumn
  • Flower: Solitary velvety deep purple to near-black blooms with a central yellow crest
  • Bulb: Small ovoid underground bulb with a fibrous protective tunic
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Care Guide

Watering

Keep soil evenly moist during flowering and leaf growth period

Fertilization

Apply diluted bulb fertilizer once when new foliage emerges. Use a low-nitrogen, phosphorus-rich fertilizer to support bulb development

Eggshell powder topdressing:Crush fully dried eggshells into a fine powder; sprinkle lightly on the soil surface around bulbs, avoiding direct contact with foliage to prevent burning
Pruning
  • Remove spent flower stems immediately after blooming to conserve bulb energy
  • Trim yellowing foliage only after it has fully died back in late spring to allow nutrients to return to the bulb
  • Thin overcrowded bulb clumps every 3–4 years in early autumn to maintain plant vigor
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Toxicity

Warning: this plant may be toxic.

Pets & Humans

Pets: ASPCA: Toxic; contains iridin which may cause vomiting, diarrhea, abdominal pain, and lethargy

Humans: Contains iridin glycosides; ingestion may cause mild gastrointestinal upset including nausea and diarrhea

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Garden Uses & Culture

Culture: N/A

Usage: Ornamental garden plant, container cultivation for indoor winter blooms