This is only one example of the multiple species of ayame that grow in Japan.
Ayame (菖蒲) Siberian Iris/Sweet Grass (Iris sanguinea)
Shoubu/Hanshoubu (菖蒲 / 花菖蒲) Japanese Iris (Iris ensata)
Kakitsubata (杜若) Rabbit Ear Iris (Iris laevigata)
Seasonal Association: Summer
The three types of iris usually referred to as Japanese iris bloom from early May to late June. This caused some ambiguity to Heian era poets. Should the iris be considered a spring flower or a summer flower? According to Haruo Shirane in Japan and the Culture of the Four Seasons, different sources originally placed it in different seasons. Shirane states that colour combinations for the juni hitoe that were indicative of the iris placed the kakitsubata in summer, however waka poets used the flower as a spring motif. A defining moment came when the influential editors of anthology Horikawa hyakushu decided to place kakistubata in spring, and hanashoubu and ayame in the summer due to their prominence in the Tango festival (held on the fifth day of the fifth month). This distinction had a lasting effect on poetry anthologies with seasonal themes, however the poets themselves continued to treat the iris as a summer motif, and by the Muromachi period, its identity had firmly returned to summer (pg 52-53).
In addition to this, the classic Japanese calendar, puts the blooming of the iris firmly into the summer months. Before the Meiji Era, Japan used a different calendar (a luni-solar calendar). According to the modern solar calendar, the traditional four seasons are as follows.
Spring: February 4-May 4 (first, second, and third months)
Summer: May 5-August 6 (fourth, fifth, and sixth months)
Autumn: August 7-November 6 (seventh, eighth, and ninth months)
Winter: November 7-February 4 (tenth, eleventh, and twelfth months)
Japan and the Culture of the Four Seasons – Haruo Shirane
This traditional seasonality, which rules all seasonal kimono motifs, would place the blooming of the iris firmly in the summer season.
A final note on seasonality, I have many pieces in my collection (see below) that are awase (lined) and not designed for summer. So what does this mean? For me, it means don’t rely on the iris to tell you what season a certain piece should be worn in. Also consider if the piece is awase (lined) or hitoe (unlined) or ro (gauze) and any other motifs present on the piece. The combination of all these elements will tell you when to wear your kimono or obi.
When To Wear It: April – June
Traditionally, the iris is linked to Boy’s Day (now Children’s Day, celebrated on May 5th) because the leaves resemble swords and the name shoubu is a homonym for militarism. Iris can often be found on boy’s kimono. Kakitsubata was made famous by its appearance in The Tales of Ise, a Heian era poetry anthology. It is also the prefectural flower of Aichi prefecture.
The most distinguishing feature of the iris is the three petals that grow downwards. These petals can be smooth or jagged, but the all have a distinct vein running down the center. Iris also have a clump of smaller petals that grow upwards. Finally, iris have long, thin leaves that usually accompany the blossom.