Giant-Rhizome Wood Sorrel (Oxalis megalorrhiza)

Giant-Rhizome Wood Sorrel

Oxalis megalorrhiza

Fleshy rhizomes store water for dry spells, a quiet survivor of arid slopes. Succulent herbaceous perennial; common name: Giant-Rhizome Wood Sorrel.

Partial sun
1–2/week
Beginner
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Plant Needs

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Sunlight Bright indirect light; tolerate partial shade, avoid harsh midday direct sun that may scorch leaves
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Watering Water when the top 2 cm of soil is completely dry; avoid overwatering to prevent rhizome rot
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Temperature Thrives in 15–25°C; tolerate light frost down to 5°C, protect from prolonged freezing temperatures
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Characteristics

  • Leaf: Trifoliate clover-like bright green leaves, folding inward at night
  • Stem: Short, fleshy stems emerging from underground tuberous rhizomes
  • Flower: Pale pink to white cup-shaped five-petaled blooms
  • Rhizome: Large, fleshy underground storage structure for water and nutrients
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Care Guide

Watering

Keep soil slightly moist, allow top layer to dry between waterings

Fertilization

Diluted balanced liquid feed once every 4 weeks. Use a diluted, low-strength fertilizer to prevent nutrient burn to sensitive rhizomes

Eggshell powder top-dress:Crush thoroughly cleaned eggshells into a fine powder; sprinkle lightly on soil surface, avoid direct contact with rhizomes to prevent irritation
Pruning
  • Remove spent flower stems promptly to encourage new bloom production
  • Trim yellowing or damaged leaves at the base to maintain rosette appearance
  • Dig up and divide overcrowded rhizomes in early spring to promote healthy growth
  • Remove any soft, rotting rhizomes during repotting to prevent spread of decay
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Toxicity

Warning: this plant may be toxic.

Pets & Humans

Pets: ASPCA confirmed toxic; ingestion causes drooling, vomiting, oral pain, and difficulty swallowing

Humans: Contains calcium oxalate crystals; ingestion causes oral burning, swollen lips, and mild nausea in large amounts

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Garden Uses & Culture

Culture: N/A

Usage: Ornamental ground cover for rock gardens; indoor container foliage plant