Yellow flag iris (Iris pseduocorus)
CAUTION! This plant contains toxins that cause minor skin irritation.
Wear appropriate clothing to prevent resinous substances from contacting skin.
To prevent seed production: “Dead-head” an iris by cutting off the flowers each year. This will keep it from producing seeds but will not kill the iris — the plant may still spread by rhizome growth. Bag and dispose of the seeds in a landfill.
To remove plant: Using a shovel, dig and pull out the entire plant, including all roots and rhizomes. Dry out root mass before composting. OR Hand cut the plant at its base after it has leafed out. This must be done annually for three to four years.
"Yellow flag iris is a perennial plant that occurs in wet areas such as ditches and marshes. Leaves arise from the base of the plant and are flattened, 3-4 ft. (0.9-1.2 m) long with a raised mid-rib. Bright yellow flowers appear in late spring to early summer. Flowers develop in groups of 2-10 and have three drooping, yellow sepals with purple-brown markings and 3 smaller, unmarked and upright yellow petals. Flowers are about 3 in. (7.6 cm) wide. Fruit are brown capsules that are 2 in. (5 cm) long. Yellowflag iris was introduced into the United States in the mid-1800s as an ornamental from Eurasia or Northern Africa. Plants can withstand a wide variety of conditions, including brackish water, acidic water and periods of drought." (Source: http://www.invasive.org/browse/subinfo.cfm?sub=5853)