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Common Name: Blue Flag
Iris versicolor is a Perennial up to 0.60 metres tall.
It has medicinal and miscellaneous uses.
Many plants in this genus are thought to be poisonous if ingested, so caution is advised[
]. The roots are especially likely to be toxic[
Plants can cause skin irritations and allergies in some people[
Eastern N. America - Newfoundland to Manitoba, south to Florida and Arkansas.
Swamps, wet meadows, scrub and by lakes and rivers[
Prefers growing in marshy conditions[
]. Very easily grown in any damp soil[
]. Prefers a heavy rich moist soil[
] and partial shade[
]. Prefers a sunny position[
Plants are hardy to about -25°c[
This species has been cultivated by the N. American Indians as a medicinal plant[
Members of this genus are rarely if ever troubled by browsing deer or rabbits[
Blue flag was one of the most popular medicinal plants amongst various native North American Indian tribes[
]. In modern herbalism it is mainly employed to detoxify the body - it increases urination and bile production and has a mild laxative effect[
]. Some caution should be exercised in its use, however, since there are reports that it is poisonous[
]. The fresh root is quite acrid and when taken internally causes nausea, vomiting, colic and purging[
]. The dried root is much less acrid[
]. This remedy should not be prescribed for pregnant women[
The root is alterative, anti-inflammatory, cathartic, cholagogue, diaphoretic, diuretic, emetic and sialagogue[
]. 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[
]. It is also stimulant for the circulatory and lymphatic system[
]. Its detoxifying effect make it useful in the treatment of psoriasis, acne, herpes, arthritis, swollen glands, pelvic inflammatory disease etc[
]. Externally, it is applied to skin diseases, wounds and rheumatic joints[
]. The roots are harvested in late summer and early autumn and are usually dried for later use[
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[
A fine blue infusion is obtained from the flowers and this can be used as a litmus substitute to test for acids and alkalis[
The leaves have been used to weave baskets and mats[
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[
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.