yellow iris
Iris pseudacorus L.


Iris pseudacorus is a herbaceous perennial that can grow up to 3-4 ft. (0.9-1.2 m) in height.
Broad, sword-shaped leaves are stiff, erect and glaucous. They measure between 1.6-3.3 ft. (0.5-1 m) long and 0.4-1.2 in. (1-3 cm) wide. Rhizomes are pink-fleshed and 0.4-1.6 in. (1-4 cm) in diameter.
Flowers are showy and bloom from April to June. Usually yellow, their color can range from nearly white to cream. Flowers are 2.75-3.5 in. (7-9 cm) wide. They are borne on erect peduncles with several flowers per stem. There are six perianth clawed segments. Three of these are upward-pointing petals and three are down-ward spreading sepals. Sepals often have purple, brown or red veins on their yellow surface.
Fruits are 1.6-2.7 in. (4-8 cm) long capsules. The capsules are 6-angled and cylindric-prismatic to ellipsoid. The average capsule contains about 120 white seeds that harden and turn brown as they mature.
Ecological Threat
It forms large clonal colonies displacing native species. The rhizomes are able to survive heavy droughts. Rhizomes and seeds can be transported downstream, further spreading the plant. Seeds can germinate even after a wetland area burns. It contains glycosides, making it toxic to grazing animals. No birds are known to disperse the seeds of this plant. Caution should be used when hand-pulling, as it can cause skin irritation.


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EDDMapS Distribution

EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit

State Regulated List

State Regulated List - This map identifies those states that list this species on their regulated list. For more information, visit

Invasive Listing Sources

Taxonomic Rank

Kingdom: Plantae
Phylum: Magnoliophyta
Class: Liliopsida
Subclass: Liliidae
Order: Liliales
Family: Iridaceae
Genus: Iris
Subject: Iris pseudacorus L.

Synonyms and Other Names

Other Common Names:
paleyellow iris


Plants - Aquatic Plants