Jamaican Vervain (Stachytarpheta jamaicensis)

Jamaican Vervain

Stachytarpheta jamaicensis

Vibrant spiked blooms draw pollinators like living blue spires. Herbaceous perennial flowering plant; common names: blue porterweed, Jamaica vervain.

Full sun
2–3/week
Beginner
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Plant Needs

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Sunlight Full sun to partial shade; tolerate brief midday shade in hot, arid climates to prevent leaf scorch
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Watering Water when the top 2 cm of soil feels dry; avoid overwatering to prevent root rot and fungal growth
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Temperature Thrives in warm tropical to subtemperate conditions; protect from frost below 10°C to avoid foliage damage
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Characteristics

  • Leaf: Opposite, ovate to lanceolate leaves with serrated margins and rough, hairy texture
  • Flower: Dense terminal spikes of small, tubular blue to violet-purple flowers
  • Stem: Square, hairy green stems characteristic of the verbena family
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Care Guide

Watering

Keep soil consistently moist but not waterlogged to support active growth and blooming

Fertilization

Diluted balanced liquid feed every 2 weeks. Avoid over-fertilization to prevent excessive foliage growth at the expense of blooms

Banana peel compost tea:Compost banana peels for 2 weeks, steep in water for 24 hours, dilute 1:20 with water for root drenching to avoid nutrient burn
Pruning
  • Deadhead spent flower spikes regularly to encourage continuous blooming throughout the growing season
  • Trim leggy stems in early spring to promote bushier, compact growth
  • Remove yellowed or damaged foliage to improve airflow and reduce pest risk
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Toxicity

Warning: this plant may be toxic.

Pets & Humans

Pets: ASPCA: No listed toxicity to cats

Humans: No documented toxic effects for humans; safe for occasional handling

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Garden Uses & Culture

Culture: N/A

Usage: Pollinator garden plant to attract bees and butterflies; used in traditional Caribbean folk medicine for mild ailments