Matilija Poppy (Romneya coulteri)

Matilija Poppy

Romneya coulteri

Its giant white blooms glow like crumpled silk under sun. Deciduous perennial herb; common name: Matilija Poppy.

Full sun
1–2/week
Moderate
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Plant Needs

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Sunlight Full sun exposure required for abundant blooming; tolerates partial shade with reduced flowering output
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Watering Water deeply but infrequently; allow top 15–20 cm of soil to dry completely between waterings to prevent root rot
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Temperature Hardy to -5°C; tolerates high summer heat when provided with well-drained soil
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Characteristics

  • Leaf: Gray-green, deeply lobed, fuzzy texture to reduce water loss
  • Flower: Large white blooms (10–15 cm diameter) with golden yellow stamens
  • Stem: Erect, branching, covered in fine white hairs
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Care Guide

Watering

Water deeply every 7–10 days during active growth; avoid overwatering to prevent root rot

Fertilization

Amend with compost once annually to support mild nutrient uptake. High-nitrogen fertilizers may reduce flower production and should be avoided

Composted banana peel tea:Steep fully composted banana peels in water for 24 hours; dilute 1:20 with water for root drench to avoid nutrient burn
Pruning
  • Cut back dead foliage to ground level in late winter to encourage vigorous new spring growth
  • Remove spent blooms promptly to extend the flowering period slightly
  • Thin overcrowded clumps every 2–3 years to improve airflow and reduce disease risk
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Toxicity

Warning: this plant may be toxic.

Pets & Humans

Pets: ASPCA confirms no toxicity to cats

Humans: No known toxic effects on humans

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Garden Uses & Culture

Culture: Symbolizes resilience in dry Mediterranean landscapes

Usage: Ornamental garden plant; short-lived cut flower for floral arrangements