Yellow flag iris

Iris pseudacorus

Native pond and stream-margin perennial with sword-shaped leaves and tall stems of bright yellow iris flowers in early summer.

Hardiness ratings

Yellow flag iris hardiness across the four zone systems
SystemRatingTemperature rangeHow to read it
USDA hardiness zone Zone 4–9 −34.4 °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 4–8 −29 °C to −1 °C Plant tolerates down to this zone
Australian (ANBG) zone Zone 1–6 −15 °C to 15 °C Plant tolerates down to this zone

Growing notes

  • Larval food plant for several moth species
  • Provides essential vertical structure for emerging dragonfly larvae to climb out of the water and complete their metamorphosis
  • WARNING: Invasive in parts of North America and Australia — listed as a noxious weed in several US states and parts of southern Australia, do not plant outside its UK and European native range without checking local regulations

Pet caution: Yellow flag iris 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 Yellow flag iris against your zones

Reference

Yellow flag iris on Wikipedia