Iris versicolor - L.
Common Name Blue Flag, Harlequin blueflag
Family Iridaceae
USDA hardiness 4-8
Known Hazards Many plants in this genus are thought to be poisonous if ingested, so caution is advised[65]. The roots are especially likely to be toxic[238]. Plants can cause skin irritations and allergies in some people[238]. Fresh root can cause nausea and vomiting. The volatile oil furfural is irritant to mucous membranes and causes larchrymation (tears) and inflammation of the eyes. Irritation of the throat and headache also reported. The sap can cause dermatitis. Should not be used internally except in small doses. Should not be used by people with allergies or sensitivities [301].
Habitats Swamps, wet meadows, scrub and by lakes and rivers[187]. Wetlands[21].
Range Eastern N. America - Newfoundland to Manitoba, south to Florida and Arkansas.
Edibility Rating  
Other Uses  
Weed Potential No
Medicinal Rating  
Fully Hardy Moist Soil Wet Soil Semi-shade Full sun

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Iris versicolor Blue Flag, Harlequin blueflag
Iris versicolor Blue Flag, Harlequin blueflag
Physical Characteristics
 icon of manicon of flower
Iris versicolor is a PERENNIAL growing to 0.6 m (2ft) by 1 m (3ft 3in).
It is hardy to zone (UK) 5. It is in flower from May to June. The flowers are hermaphrodite (have both male and female organs) and are pollinated by Insects.The plant is self-fertile.
Suitable for: light (sandy) and medium (loamy) soils. Suitable pH: acid, neutral and basic (alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist or wet soil.

Iris boltoniana, Iris caurina, Iris dierinckii, Limniris versicolor.

 Bog Garden;
Edible Uses
None known
Medicinal Uses

Plants For A Future can not take any responsibility for any adverse effects from the use of plants. Always seek advice from a professional before using a plant medicinally.

Alterative;  Antiinflammatory;  Cathartic;  Cholagogue;  Diuretic;  Emetic;  Sialagogue;  Stimulant.

Blue flag was one of the most popular medicinal plants amongst various native North American Indian tribes[213]. In modern herbalism it is mainly employed to detoxify the body - it increases urination and bile production and has a mild laxative effect[254]. Some caution should be exercised in its use, however, since there are reports that it is poisonous[222]. The fresh root is quite acrid and when taken internally causes nausea, vomiting, colic and purging[4, 238]. The dried root is much less acrid[4]. This remedy should not be prescribed for pregnant women[238]. The root is alterative, anti-inflammatory, cathartic, cholagogue, diaphoretic, diuretic, emetic and sialagogue[21, 46, 165, 238]. Taken internally as a tea, the root has been used as a strong laxative or emetic that also acts strongly on the liver and promotes the excretion of excess body fluids[4, 213]. It is also stimulant for the circulatory and lymphatic system[165]. Its detoxifying effect make it useful in the treatment of psoriasis, acne, herpes, arthritis, swollen glands, pelvic inflammatory disease etc[238, 254]. Externally, it is applied to skin diseases, wounds and rheumatic joints[238]. The roots are harvested in late summer and early autumn and are usually dried for later use[4, 238]. The roots were boiled in water and then mashed to make a poultice which was used to relieve the pain and swelling associated with sores and bruises[213].


Other Uses
Litmus;  Repellent;  Weaving.

A fine blue infusion is obtained from the flowers and this can be used as a litmus substitute to test for acids and alkalis[4]. The leaves have been used to weave baskets and mats[257]. Some native North American Indian tribes used the root as a protection against rattlesnakes. It was believed that, so long as the root was handled occasionally to ensure the scent permeated the person and their clothes, rattlesnakes would not bite them. Some tribes even used to chew the root and then hold rattlesnakes with their teeth and were not bitten so long as the scent persisted[257].
Cultivation details
Prefers growing in marshy conditions[1]. Very easily grown in any damp soil[42]. Prefers a heavy rich moist soil[4] and partial shade[188]. Prefers a sunny position[233]. Plants are hardy to about -25°c[187]. This species has been cultivated by the N. American Indians as a medicinal plant[207, 213]. Members of this genus are rarely if ever troubled by browsing deer or rabbits[233].
Seed - best sown as soon as it is ripe in a cold frame. Stored seed should be sown as early in the year as possible in a cold frame. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in the greenhouse or cold frame for their first year. Plant out into their permanent positions in late spring or early summer. Division, best done in early autumn after flowering, but can also be done in mid-spring. Very easy, larger clumps can be replanted direct into their permanent positions, though it is best to pot up smaller clumps and grow them on in a cold frame until they are rooting well. Plant them out in the spring.
Other Names
Found In
Weed Potential

Right plant wrong place. We are currently updating this section. Please note that a plant may be invasive in one area but may not in your area so it’s worth checking.

Conservation Status
IUCN Red List of Threatened Plants Status :
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Readers comment
Anju   Wed Oct 10 2007
I am taking homeopathic medicine for Psoriasis relisf since 3 months.. it is getting worse.. I took graphites, Psorianum and now, Iris and Barberis... please suggest
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Subject : Iris versicolor  

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