Yellow Iris
(Iris pseudacorus)
Biological Category
Plants
NY Legal Status
Prohibited
Species Type
Other Herbaceous
DESCRIPTION
An herbaceous perennial in the Iris family (Iridaceae).
Grows to a height of 3 – 4 feet. The broad, sword-shaped leaves are stiff, erect, and green with a grayish-blue cast. The leaves are 1.6-3.3 feet long and 0.4-1.2 inches wide and have a central ridge on both sides of the blades.
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Leaves 1.6-3.3 feet long and 0.4-1.2 inches wide and have a central ridge on both sides of the blades.
Flowers: white to cream or often yellow, borne on erect peduncles with several flowers on each stem and bloom from April-June.
Fruit capsule: is 6-angled, egg-shaped, and contains around 120 seeds that start out white then turn
pale brown.
Seeds: buoyant and can be dispersed over long distances by water.
Rhizomes: pink fleshed, and 0.4-1.6 inches in diameter and may extend vertically 4 to 8 inches deep. It spreads vegetatively through the break-up of rhizomes or from abundantly produced seeds.
Europe and the British Isles, Western Asia, North Africa, and the Mediterranean region; introduced for ornamental wetland habitats, for erosion control or to remove metals in sewage treatment plants, as it is effective at removing nutrients and trapping sediments.
Pale yellow iris can survive a range of environmental conditions. It grows in fresh or brackish water often occupies habitats that have low oxygen. It can be found in wetlands, shorelines, rocky shores, ditches, stream-banks, floodplain forests, and areas of shallow water. Yellow iris will tolerate high soil acidity (pH from 3.6-7.7) and requires high levels of nitrogen for optimum growth.
Iris pseudacorus are very competitive against native plants due to their ability to form dense colonies and impenetrable thickets, ultimately displacing the native plants, and reducing habitat availability for animals as a result. Thriving in wetlands, their buoyant seeds are spread over long distances by water. All parts of the plant are poisonous to livestock and other animals. The rhizomes of the plants can survive harsh droughts, allowing for survival through dry conditions. The roots of the iris create a mat which compacts soil and prevents seed germination of native plants like cattails and native irises.
Caution should be used if pulling out this plant because it can cause skin irritation; remove seed pods to help control population expansion; dig up small infestations; remove entire rhizome root system; use chopping machines for larger infestations; burn where conditions allow.
It can be effectively controlled using any of several readily available general use herbicides such as glyphosate that is approved for wetland habitats. Follow label and state requirements.
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