Bracken fern

Pteridium aquilinum

Globally widespread fern of acidic moors and open woodland. Cut fronds make exceptional potash-rich mulch and compost feedstock.

Hardiness ratings

Bracken fern hardiness across the four zone systems
SystemRatingTemperature rangeHow to read it
USDA hardiness zone Zone 3–9 −40 °C to −1.1 °C Plant tolerates down to this zone
RHS hardiness rating H7 down to −20 °C Plant needs at least this level of cold tolerance
Canadian plant hardiness zone Zone 3–9 −34 °C and warmer Plant tolerates down to this zone
Australian (ANBG) zone Zone 1–5 −15 °C to 10 °C Plant tolerates down to this zone

Growing notes

  • Dynamic accumulator — extraordinarily high potassium concentration in fronds (5%+ of dry weight)
  • Bracken contains carcinogenic compounds (ptaquiloside and others) — do not eat under any circumstance, despite some traditional uses; wear gloves and a mask when harvesting cut fronds
  • Spreads by deep rhizomes — useful for soil-binding on slopes but invasive in pastures

Pet caution: Bracken fern is listed as potentially harmful to cats and/or dogs. Keep pets from grazing on it, and contact a vet if you suspect your animal has eaten some.

Categories

Related plants

Cross-check Bracken fern against your zones

Reference

Bracken fern on Wikipedia