Scientific Name:
Iris pseudacorus L., Sp. Pl. 38 (1753)
Vernacular Name(s):
yellow flag

Clumps very leafy, many-flowered, to 1 m high, dark green, ± glaucous, purple at base. Rhizome c. 3 cm diam., reddish-brown. Leaves c. = stems, 2–3 cm wide, cross-veinlets apparent when leaf is held up to light, midrib distinct. Stems terete, with several long leaves. Inflorescence usually branched, central axis and each branch terminated by 2–5-flowered clusters. Flowers to 12 cm diam., yellowish, varying from golden-orange to very pale cream, without scent; pedicels long, stout, > ovary; tube funnel-shaped, ± ½ length of ovary; outer segments 7 cm long, oval-oblong, limb c. 4 cm wide, very drooping, abruptly narrowed to dark brown-veined claw; inner segments c. 3 cm long, shorter and narrower but more erect than style-branches. Style-branches oblong, bifid crest fimbriate. Capsule c. 5 × 2 cm, oblong-elliptic, beaked; seeds brown, ± trigonous.

[From: Healy and Edgar (1980) Flora of New Zealand. Volume 3.]


Flowering: Nov.–Dec.

Biosecurity New Zealand 2012: Regional Pest Management Strategies Database.
Biosecurity New Zealand 4 Aug 2011: Unwanted Organisms Register.
Biosecurity New Zealand 2008: National Plant Pest Accord. MAF Biosecurity New Zealand, Wellington.
Howell, C. 2008: Consolidated list of environmental weeds in New Zealand. DOC Research & Development Series 292: 42.
Linnaeus, C. 1753: Species Plantarum. Impensis Laurentii Salvii, Stockholm.
Ministry for Primary Industries 23 Feb 2017: Unwanted Organisms Register. Version 02.01.02.