Field Horsetail (Equisetum arvense)

Field Horsetail

Equisetum arvense

Segmented stems carry prehistoric quietude, a living fossil from the Paleozoic era. Herbaceous perennial; common name: common horsetail.

Partial sun
2–3/week
Moderate
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Plant Needs

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Sunlight Thrives in partial sun to full shade; tolerates dappled woodland light, avoids intense midday direct sun
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Watering Maintain consistently moist soil; avoid complete drying, but do not allow standing water to prevent root rot
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Temperature Hardy to frosty temperate climates; avoid prolonged temperatures above 28°C which can scorch foliage
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Characteristics

  • Stem: Two distinct stem types: sterile green segmented stems with whorled branches; fertile brown unbranched stems bearing terminal spore cones
  • Leaf: Reduced to tiny, scale-like sheaths wrapped tightly around stem nodes
  • Root: Deep, spreading rhizomatous root system that forms dense colonies
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Care Guide

Watering

Keep soil evenly moist; water when top 1 cm of substrate feels dry

Fertilization

Apply diluted, balanced liquid feed once every 6 weeks. Avoid high-nitrogen fertilizers which can promote weak, leggy stem growth

Banana peel tea:Steep fully composted banana peels in water for 3 days, dilute 1:20 for root drench; discard solid peels to prevent odor and pest attraction
Pruning
  • Cut back brown, spent fertile stems after spore release in early spring
  • Thin overcrowded sterile stems to improve airflow and reduce colony spread
  • Trim spreading rhizomes in late autumn to contain invasive growth in garden beds
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Toxicity

Warning: this plant may be toxic.

Pets & Humans

Pets: ASPCA: Not explicitly listed, but ingestion may cause mild gastrointestinal upset due to thiaminase content

Humans: Contains thiaminase enzyme that may cause vitamin B1 deficiency with prolonged, large-scale ingestion; mild gastrointestinal irritation with acute ingestion

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Garden Uses & Culture

Culture: N/A

Usage: Traditional medicinal use as a diuretic and anti-inflammatory; consult a healthcare professional before internal use