Iris - Iris

Japanese: アイリス - あいりす

A general term for the genus Iris in the Iridaceae family (APG classification: Iridaceae). When simply referred to as iris, it often refers to the species cultivated horticulturally. Iris means rainbow in Greek, and was named after the beautiful rainbow-like flowers. This genus is distributed in the temperate zone of the Northern Hemisphere, between 20 and 60 degrees north latitude, and grows widely in Asia, Europe, North Africa, and North America, with over 230 to 300 known species. Eight species grow wild in Japan: Japanese iris, Japanese iris, Japanese iris, Iris japonica, Iris serrata, Iris umbellata, Iris cernua, Iris amaranth, and Iris lily. The shape of the flower varies widely, but it is said to be iris-shaped, with three outer petals (perianth) and three smaller inner petals (perianth), a three-lobed style (pistil), and an anther (stamen) at the bottom. The flower color is often purple-blue, but it can also be white, yellow, reddish brown, brownish brown, or black-purple. The pure scarlet color is somewhat similar to that of I. fulva , which grows wild in central America, but it is said that there are no original species with this color type.

Most are perennial, but some are bulbous and planted in the fall. They are generally cold-tolerant, and their characteristics vary, with some preferring wetlands and others preferring drylands. Those that prefer wetlands tend to be tall and have majestic stems and leaves. Those that prefer drylands tend to be dwarf and have short stems and leaves. They can be broadly divided into bulbous and rhizomatous species. Bulbous species are also called bulbous irises, and are characterized by having no roots during dormancy, with varieties such as Dutch iris, English iris, Spanish iris, and reticulata iris. Representative rhizomatous species include German iris, Japanese iris, Japanese iris, Japanese iris, Japanese water iris, Japanese iris, Japanese iris, Japanese iris, Japanese iris, Japanese iris, and Louisiana iris, and there is also a theory that those with whiskers near the base of the lower petals are further subdivided into a separate lineage. In addition to these, two or three other species are known, including bulbous but rhizomes and those with fleshy rhizomes.

[Torasaburo Kawabata May 21, 2019]

Cultivation

Dutch iris/ I. × hollandica Hort. ex Todd., a representative bulb species, is also called Dutch iris. It is a cross-breeding in the Netherlands of several species native to the Mediterranean coastal region. It is a cold-tolerant species that usually leaves in autumn, but dies at temperatures below -10°C. Representative varieties include White Wedgwood, Yellow Queen, Ideal, Blue Ribbon, and National Velvet. Bulbs are dug up in mid- to late June when the leaves are half-withered, dried in a well-ventilated shade, stored, and planted in October. Reproduction is by bulb division. Depending on the size of the bulb, 7-8 cm bulbs should be planted one bulb per 5 cm square, and covered with soil just enough to cover the bulb. Fertilizer should be applied generously as basal fertilizer.

German iris ( I. germanica L.), a representative rhizome species, is also called German iris. Many varieties have been created by crossbreeding several species native to Europe, and many excellent varieties have been further improved in America. They are called rainbow flowers, and have a wide variety of flower colors. Many varieties have petals that spread out horizontally and are fragrant, which are the result of the best breeding techniques. They are cultivated in the same way as Dutch irises, but are suited to dry areas with good sunlight and drainage, and if grown well, they will produce excellent flowers for 2 to 3 years without replanting. Both are widely used as cut flowers, potted plants, flower beds, gardens, and rock gardens, and are also popular as seasonal flowers for the Boy's Day festival. The drawback is that they are susceptible to white blight and soft rot, so preventing these diseases is the key to producing excellent flowers.

[Torasaburo Kawabata May 21, 2019]

Cultural history

Iris, which is said to have been brought back from Syria by the Egyptian king Thutmose III in the 15th century BC, has a long history of cultivation and was used in perfume in ancient Greece and Rome. In medieval Europe, the dried root (orris root) of I. florentina L. (Japanese name: Nioi Iris) was made into a necklace to ward off illness and became very popular. The fleur-de-lis, a heraldic version of the iris, was used by King Clovis in the 5th century and was the coat of arms of the French royal family until the 19th century. There is also a theory that it literally means lily.

[Hiroshi Yuasa May 21, 2019]

iris
There are six tepals. The base of the outer tepal has a purple twill pattern on a yellow background. It grows wild in sunny mountainous areas. The flowering season is from May to July. ©Seishohmaru ">

iris

Ichihatsu
The flowering season is from April to May. The outer tepals are obovate, and the inner surface below the center is densely covered with white fleshy protuberances with purple spots. ©Seishohmaru ">

Ichihatsu

Iris
The leaves are sword-shaped and 30-70cm long. In May and June, blue-purple flowers bloom at the end of the flower stalk. The outer petals droop and have white or pale yellow markings along the midvein. ©Seishohmaru ">

Iris

Yellow iris
The leaves are broad and grow to over 1m, and in May and June, they produce yellow or white flowers with thin petals. They were introduced to Japan as a horticultural variety .

Yellow iris

Iris japonica
The flower stalk branches upward and produces white to pale purple flowers. It is the only evergreen species in the Iridaceae family. ©Shogakukan ">

Iris japonica

Japanese Iris
A horticultural variety of Japanese iris. Improvement and breeding began in the Edo period, and there are many varieties. ©Shogakukan Photo by Masatoshi Hirose ">

Japanese Iris

Iris arvensis
It grows in clusters in subalpine wetlands and high moors, and blooms blue-purple flowers in July and August. The outer petals are broadly obovate and drooping, with yellow and purple tiger stripes at the base. ©Shogakukan Photo by Fujio Aoyama ">

Iris arvensis

Dutch Iris
It is a representative bulbous iris, and its flower colors include blue, purple, white, and yellow. Also known as Dutch iris .

Dutch Iris

German Iris
A representative species of rhizome plant, it is known as the "rainbow flower" because of its rich variety of flower colors. Also known as German iris ©Shogakukan ">

German Iris

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

Japanese:

アヤメ科（APG分類：アヤメ科）イリス属の総称。単にアイリスとよぶ場合、園芸的に栽培する種の総称をさすことが多い。イリスはギリシア語で虹(にじ)を意味し、虹のように美しい花からつけられた。本属は北半球の温帯、北緯20～60度に分布し、アジア、ヨーロッパ、北アフリカ、北アメリカに広く生育し、230種から300種余が知られている。日本にはノハナショウブ、アヤメ、カキツバタ、シャガ、ヒメシャガ、エヒメアヤメ、ヒオウギアヤメ、ヒオウギの8種が自生する。形態は変化に富むが、花形はアヤメ形といわれ、3枚の外側の花弁（外花被(かひ)）およびそれより小さい内側の3枚の花弁（内花被）と、3裂した花柱（雌しべ）および下部に各1個ずつの葯(やく)（雄しべ）からなる。花色は紫青色系が多いが、白、黄、赤褐色、茶褐色、黒紫色などもある。純粋の緋紅(ひこう)色系はアメリカ中部に自生するフルバ（チャショウブ）I. fulvaがやや近いが、原種にはこの色系統のものはないとされる。

　宿根多年生のものが多いが、秋植え球根性のものもある。一般に耐寒性が強く、湿地を好むもの、乾燥地を好むものなど性質に変化がある。湿地好みのものは高性型が多く、茎葉が雄大である。乾燥地好みのものは矮性(わいせい)で茎葉も短いものが多い。大別して鱗茎(りんけい)種と根茎種に分ける。鱗茎種は球根アイリスともいい、休眠中は根がないのが特徴で、ダッチ・アイリス、イングリッシュ・アイリス、スパニッシュ・アイリス、レティキュラータ・アイリスなどの品種がある。根茎種は代表的なものにジャーマン・アイリス、ハナショウブ、アヤメ、カキツバタ、キショウブ、シャガ、イチハツ、ルイジアナなど多くの種類があり、さらに下弁の基部近くにひげのあるものを別系統に細分する説もある。これらのほかに、球根性を呈しながら根茎のもの、多肉質の根茎をもつものなど、2～3種が知られる。

［川畑寅三郎　2019年5月21日］

栽培

鱗茎種の代表種であるダッチ・アイリスDutch iris/I. × hollandica Hort. ex Todd.はオランダアヤメともいう。地中海沿岸地方原産の数種をオランダで交雑育種したもの。普通秋から出葉する耐寒種であるが、零下10℃以下では枯死する。代表的品種にホワイト・ウェッジウッド、イエロー・クイン、アイデアル、ブルー・リボン、ナショナル・ベルベットなどがある。球根は、6月中・下旬に葉が半枯れになったときに掘り上げ、風通しのよい日陰に乾かして貯蔵し、10月に植える。繁殖は分球による。球根の大きさにもよるが7～8センチメートル球では5センチメートル平方に1球ずつ植え、覆土は球根が隠れる程度にする。肥料は多めに基肥として施す。

　根茎種の代表種であるジャーマン・アイリスGerman iris/I. germanica L.はドイツアヤメともいう。ヨーロッパ原産の数種が交雑育種され、多くの品種がつくられ、さらにアメリカで改良された優れた品種が多い。レインボー・フラワーといわれるほどで、花色の変化に富む。また、花弁が横に張る品種や芳香も放つ品種など、育種技術の粋を凝らしたものが多い。栽培はダッチ・アイリス同様であるが、日当り、排水ともよい乾燥地に適し、生育がよければ2～3年は植えかえをしなくても優れた花をつける。ともに切り花、鉢植え、花壇、庭園、ロック・ガーデンなどに広く用いられ、端午(たんご)の節供の季節花としても愛用される。白絹(しらきぬ)病や軟腐(なんぷ)病に弱いのが難点で、これを防ぐことが、優秀な花を咲かせるポイント。

［川畑寅三郎　2019年5月21日］

文化史

エジプト王トゥトメス3世が紀元前15世紀にシリアから持ち帰ったといわれるアイリスは、栽培の歴史が古く、古代ギリシアやローマでは香水に使われた。中世のヨーロッパではフロレンティーナ（和名ニオイイリス）I. florentina L.の乾燥した根（オリス根）が、病気除(よ)けの首飾りにされて大流行した。またアイリスを紋章化したフルール・ド・リスは、5世紀にクロービス王が使って以来、19世紀までフランス王家の紋章であった。なお、これを字義通りユリとする説もある。

［湯浅浩史　2019年5月21日］

アヤメ
花被片は6枚。外花被片の基部には、黄色地に紫色の綾目模様がある。日当たりのよい山地に多く自生する。花期は5～7月©Seishohmaru">

アヤメ

イチハツ

カキツバタ

キショウブ

シャガ

ハナショウブ

ヒオウギアヤメ

ダッチ・アイリス

ジャーマン・アイリス

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