yellow iris USDA PLANTS Symbol: IRPS
U.S. Nativity: Exotic
Habit: Aquatic Plants Forbs/Herbs
Iris pseudacorus L.

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Taxonomic Rank: Liliopsida: Liliales: Iridaceae
Synonym(s): paleyellow iris
Native Range: western Asia, North Africa; western Europe, N. Africa (BAIL);

Appearance
Iris pseudacorus is a herbaceous perennial that can grow up to 3-4 ft. (0.9-1.2 m) in height.
Foliage
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
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.
Fruit
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.

Identification, Biology, Control and Management Resources

Selected Images from Invasive.orgView All Images at Invasive.org


Plant(s); in flower
Todd Pfeiffer, Klamath County Weed Control, Bugwood.org
Additional Resolutions & Image Usage

Flower(s);
Nancy Loewenstein, Auburn University, Bugwood.org
Additional Resolutions & Image Usage

Flower(s);
Nancy Loewenstein, Auburn University, Bugwood.org
Additional Resolutions & Image Usage

Fruit(s); fruit.
Joseph M. DiTomaso, University of California - Davis, Bugwood.org
Additional Resolutions & Image Usage

Flower(s); pale yellow form
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage

Flower(s);
Nancy Loewenstein, Auburn University, Bugwood.org
Additional Resolutions & Image Usage

Fruit(s);
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage

Plant(s); along drainage area
Nancy Loewenstein, Auburn University, Bugwood.org
Additional Resolutions & Image Usage

Plant(s); along drainage area
Nancy Loewenstein, Auburn University, Bugwood.org
Additional Resolutions & Image Usage

Infestation;
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage

Seed(s);
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage

Seed(s);
Steve Hurst, USDA NRCS PLANTS Database, Bugwood.org
Additional Resolutions & Image Usage

Root(s); Inside of cut rhizome
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage

Root(s); large rhizome.
Joseph M. DiTomaso, University of California - Davis, Bugwood.org
Additional Resolutions & Image Usage

Plant(s);
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage

Plant(s); Britton, N.L., and A. Brown. 1913. Illustrated flora of the northern states and Canada. Vol. 1: 540.
USDA PLANTS Database, USDA NRCS PLANTS Database, Bugwood.org
Additional Resolutions & Image Usage

Plant(s); USDA NRCS. Wetland flora: Field office illustrated guide to plant species. USDA Natural Resources Conservation Service.
USDA PLANTS Database, USDA NRCS PLANTS Database, Bugwood.org
Additional Resolutions & Image Usage

EDDMapS Distribution:
This map is incomplete and is based only on current site and county level reports made by experts and records obtained from USDA Plants Database. For more information, visit www.eddmaps.org
 


State(s) Where Reported invasive.
Based on state level agency and organization lists of invasive plants from WeedUS database.

U.S. National Parks where reported invasive:
Colonial National Historical Park (Virginia)



Invasive Listing Sources:
California Invasive Plant Council
Connecticut Department of Environmental Protection
Delaware Natural Resources and Environmental Control, 2004
Faith Campbell, 1998
Hoffman, R. & K. Kearns, Eds. 1997. Wisconsin manual of control recommendations for ecologically invasive plants. Wisconsin Dept. Natural Resources, Bureau of Endangered Resources. Madison, Wisconsin. 102pp.
Jil M. Swearingen, Survey of invasive plants occurring on National Park Service lands, 2000-2007
John Randall, The Nature Conservancy, Survey of TNC Preserves, 1995.
Maryland Department of Natural Resources, 1994
Mid-Atlantic Exotic Pest Plant Council, 2005
Native Plant Society of Oregon, 2008
New Hampshire Invasive Species Committee. 2005. Guide to Invasive Upland Plant Species in New Hampshire. New Hampshire Department of Agriculture,  Markets and Food Plant Industry Division and New Hampshire Invasive Species Committee.
Pacific Northwest Exotic Pest Plant Council, 1998
Tennessee Exotic Pest Plant Council
Vermont Department of Environmental Conservation
Virginia Invasive Plant Species List