Introduced from South America as an aquatic ornamental
30 t0 90 centimetres tall

Yellow flag iris
(Iris pseudacorus)

Quick Identification

Showy yellow flowers
Long, sword-like leaves
Only completely yellow-flowered iris in North America
Forms dense colonies in wet areas

Impact
This plant increases steam sedimentation which affects fish. It can grow big enough to block stream access and can alter flows causing stream bank erosion. Once established it is a hard work to remove.

Management
Digging can successfully control small, isolated patches if the entire rhizome mass is removed and treatment is repeated every year for several years to weaken and eventually kill the plant. Wear gloves.

Flower
One to several large, yellow flowers on each stem. There are three upward pointing petals and three downward pointing, tongue shaped sepals; often adorned with brown spots or purple veins.

Leaves & Stems
Leaves are 0.5 to 1 meter long, sword-like, flat, with pointy tip; 8 to 25 mm wide; raised midribs and smooth edges; arranged with sheathing, fan-like. Branched, flowering stems have few to no leaves.

Roots
Thick, fleshy rhizomes may extend 10 to 20 cm deep. Rhizomes often form horizontal mats, and can go for several months without water.

Reproduction & Dispersal
By rhizomes and seeds. Seeds germinate and grow well after being burnt. Mainly spread by people but can fragment and spread down water ways.

Seeds

Fruit is an erect, three-chambered, glossy-green cylindrical capsule. Each chamber contains many disc-shaped, pitted, pale brown seeds densely packed in vertical rows.

Preferred Habitat
Found in moist soils near lakes and ponds, stream banks, irrigation ditches and wetlands.

Interesting Facts
Has been used for erosion control, sewage treatment, and is known to remove metals from wastewater. Can be toxic to humans and animals. Yellow flag iris continues to be sold through garden dealers.

Introduced from South America as an aquatic ornamental

30 t0 90 centimetres tall

Yellow flag iris (Iris pseudacorus)

Quick Identification

Showy yellow flowers

Long, sword-like leaves

Only completely yellow-flowered iris in North America

Forms dense colonies in wet areas

Impact This plant increases steam sedimentation which affects fish. It can grow big enough to block stream access and can alter flows causing stream bank erosion. Once established it is a hard work to remove.

Management Digging can successfully control small, isolated patches if the entire rhizome mass is removed and treatment is repeated every year for several years to weaken and eventually kill the plant. Wear gloves.

Flower One to several large, yellow flowers on each stem. There are three upward pointing petals and three downward pointing, tongue shaped sepals; often adorned with brown spots or purple veins.

Leaves & Stems Leaves are 0.5 to 1 meter long, sword-like, flat, with pointy tip; 8 to 25 mm wide; raised midribs and smooth edges; arranged with sheathing, fan-like. Branched, flowering stems have few to no leaves.

Roots Thick, fleshy rhizomes may extend 10 to 20 cm deep. Rhizomes often form horizontal mats, and can go for several months without water.

Reproduction & Dispersal By rhizomes and seeds. Seeds germinate and grow well after being burnt. Mainly spread by people but can fragment and spread down water ways.

Seeds

Preferred Habitat Found in moist soils near lakes and ponds, stream banks, irrigation ditches and wetlands.

Interesting Facts Has been used for erosion control, sewage treatment, and is known to remove metals from wastewater. Can be toxic to humans and animals. Yellow flag iris continues to be sold through garden dealers.

Yellow flag iris
(Iris pseudacorus)

Impact
This plant increases steam sedimentation which affects fish. It can grow big enough to block stream access and can alter flows causing stream bank erosion. Once established it is a hard work to remove.

Management
Digging can successfully control small, isolated patches if the entire rhizome mass is removed and treatment is repeated every year for several years to weaken and eventually kill the plant. Wear gloves.

Flower
One to several large, yellow flowers on each stem. There are three upward pointing petals and three downward pointing, tongue shaped sepals; often adorned with brown spots or purple veins.

Leaves & Stems
Leaves are 0.5 to 1 meter long, sword-like, flat, with pointy tip; 8 to 25 mm wide; raised midribs and smooth edges; arranged with sheathing, fan-like. Branched, flowering stems have few to no leaves.

Roots
Thick, fleshy rhizomes may extend 10 to 20 cm deep. Rhizomes often form horizontal mats, and can go for several months without water.

Reproduction & Dispersal
By rhizomes and seeds. Seeds germinate and grow well after being burnt. Mainly spread by people but can fragment and spread down water ways.

Preferred Habitat
Found in moist soils near lakes and ponds, stream banks, irrigation ditches and wetlands.

Interesting Facts
Has been used for erosion control, sewage treatment, and is known to remove metals from wastewater. Can be toxic to humans and animals. Yellow flag iris continues to be sold through garden dealers.