The Japanese Iris

A type of beardless iris, the Japanese iris (Iris ensata) is highly revered in Japanese culture. The Japanese gardener arranges his iris garden by color, with white flowers beginning a parade of gradually deepening hues within a row, ending with the deepest purple. The Japanese iris produces large, ruffled flowers with variegated, veined or dotted patterns. Although Japanese irises have specific cultural requirements, they are not difficult to grow. They are lovely as cut flowers, either alone or included with other flowers in a bouquet.


The Japanese irises commonly cultivated today are descended from wild irises, or Hanashobu, as they are known in Japan. The first known mention of these plants occurs in a Japanese book by Jien, who lived from 1155 to 1225, and the experts at the American Iris Society claim that the Japanese actively hybridized the plants for 500 years. The Japanese iris was introduced into the United States in 1869 but was discarded by the public, due to its Japanese heritage, during the the second World War. Since then, it has experienced a resurgence in popularity and is widely grown throughout the United States.


In Japan, irises symbolize heroism, strength and protection. The leaves, which bear a resemblance to swords, were placed in Japanese boys’ bath water to herald a fighting spirit. As well, iris leaves play a central role in the annual May 5th Tango-no-Sekku -- Boy’s Day -- celebration. The leaves, which are believed to ward off illness, are soaked in hot water for the Shobu-yu, or iris hot bath, which whole villages take part in. The Tango-no-Sekku festival also includes drinking sake laced with chopped iris leaves and the placement of iris leaves in the eaves of homes to ward off both fire and evil spirits. Give the iris, or a bouquet, to a friend who needs strength and protection.


While many plants are particular in their cultural requirements, those of the Japanese iris dictate its height, the strength of its stems and flowers, and its color. Ensata Gardens, a Japanese iris nursery, doesn’t list individual plant height for its customers, since height is entirely culture-dependent. Water is the Japanese iris’ best friend. Japanese gardeners not only soak the soil daily during the growing season, they allow several inches of water to stand on the surface of the soil.


Japanese iris plants, particularly those grown in the eastern regions of the United States, are susceptible to the iris borer, a type of moth larvae. Signs of an iris borer infestation include wet-looking stains on leaf margins, tiny holes in the foliage and saw-dust-like droppings at the base of the Japanese iris. Attacking the problem when these early symptoms are first noticed may save the plant from further damage. Use a systemic insecticide with the active ingredient dimethoate to prevent the borer from infesting your iris and to treat an active infestation.

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