#950 Iris pseudacorus Common Names: yellow flag, water flag, yellow iris Family: Iridaceae (iris Family) Get link to this Profile or click for data record #950

Jack grows yellow iris along the margins of the Catfish Pond where it can survive extremes of both high (drowning) and low (high and dry) but is constrained from wandering into nearby natural areas. Click to download a large version of this image.

Location
The irises are native to temperate regions throughout the northern hemisphere in North America, Europe and Asia. Yellow flag occurs naturally in Europe, eastward to Siberia and south to northern Africa. It is an iris of wet places, usually growing in shallow water in a marsh or at the edge of a stream or pond. Yellow flag has naturalized in wet places over much of the eastern United States, and is often rather common in marshes and along streams from New England to Florida.

Culture
Light: Yellow flag should be in full sun when grown in water or very moist soils. On drier sites, the plant should receive some shade from the midday sun.
Moisture: Yellow flag should be kept moist. It can be grown at the margins of ponds, lakes or streams, or directly in the shallow water, where it attains its greatest size and vigor. Plants grown on drier sites should be watered frequently and can be expected to stay smaller and spread less than those grown in the water.
Hardiness: USDA Zones 4 - 9.
Propagation: Propagate yellow flag by division in late summer after flowering has ceased, or harvest ripe seed in fall. Seeds produce variable plants and take two years to flower. On a good, wet site, yellow flag will probably seed itself, and could become a nuisance if not restricted.

Yellow flag grown under drier garden conditions is smaller and is not so apt to be invasive as when planted in constantly moist soils.

Yellow flag has had many uses over the centuries. The dried and powdered roots were used as a snuff; the seeds were roasted and prepared like coffee; the flowers were used to make a yellow dye; the rhizomes were used as a powerful laxative. Cut flowers last well and the dried fruit capsules are very attractive in arrangements.

Features
Irises have been bred, hybridized and selected for more than 150 years. There are some 300 species of irises and more than a thousand named hybrids and selections. The many species, hybrids and selections of irises are divided into two main groups: rhizomatous and bulbous. The rhizomatous irises are further divided into three groups: bearded, with a tuft of hairs near the base of each fall; crested (a.k.a. Evansia), with a raised crest where the beard would be; and beardless. Yellow flag is one of the rhizomatous beardless irises. The genus is named for the Greek goddess, Iris, who walked on the rainbow between heaven and Earth, leaving colorful flowers in her footsteps. Yellow flag is probably the model for the "Lily of France" emblem of the French kings, in use since the 12th century.

Checkout the American Iris Society, where iris lovers gather to discuss, enjoy and trade irises.

WARNING
Yellow flag could spread and dominate a wetland site if allowed. It has become established in natural areas in North America, but apparently has not become a problem severe enough to be placed on restricted plant lists - yet. Do not plant yellow iris in natural bodies of water or anywhere it might escape into the wild.

Steve Christman 5/1/02; updated 10/12/03

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