Japanese name: キショウブ（黄菖蒲） Scientific name:Iris pseudacorus
[Overview]
An evergreen perennial that grows at the water's edge.
It has well-developed rhizomes.
The leaves are sword-shaped, 60–100 cm long and 2–3 cm wide.
The flowers are borne on a flower stalk 60–100 cm tall, which usually branches into 3.
The flowers are 8 cm across and yellow; there are 6 tepals, and the 3 outer tepals are large, ovate and hanging down, with a brown net-like pattern at the base.
The inner tepals are very small, spatulate, 2 cm long and 0.5 cm wide, and stand erect.
The flowers wither in a day and bloom one after another.
[History]
It was imported as an ornamental plant in the Meiji period, but it reproduces vigorously and has now become naturalized in many places.
It is designated as an Invasive Alien Species Requiring Caution.
