Japanese iris is a tall, beardless iris of wet ground that blooms in midsummer, after bearded and Siberian irises have finished. Each drooping outer petal, or , has a yellow patch at its base. It is native to Japan, Korea, China, and eastern Russia and is grown in gardens across the US; it is also called Japanese water iris.
Appearance
- Growth form
- A clump-forming perennial 2–4 ft (60–120 cm) tall that spreads from .
- Leaves
- Long, sword-shaped leaves with a raised midrib.
- Flowers
- Wild plants are reddish purple; garden forms come in white, pink, lavender, purple, and blue.
- Flowering time
- Midsummer
- Fruit
- A brown capsule about 1 in (2.5–3 cm) long that splits to release flat, reddish-brown seeds.
Look-alikes
Where it lives
- Typical habitats
- Marshes
- Pond edges
- Wet meadows
- Gardens
- Range
- Native to East Asia, from eastern Siberia to Japan. In the US it is known mainly as a garden plant.
- Preferred conditions
- Likes full sun to part shade and damp, rich, acidic soil (pH below 6.0) at the water's edge. It can stand in water during the growing season but not through winter.
Growing it
- Care
- Grows in USDA zones 4–9. Divide clumps about every three years after flowering. Deer tend to leave it alone.
- Toxicity
- Mildly toxic if eaten, causing stomach upset; the sap can irritate skin. Listed as a concern for cats, dogs, and horses.
Name and classification
- About the name
- Formerly sold under the name Iris kaempferi.
- Varieties and forms
- Japanese gardeners have bred this iris for at least five centuries, and American breeders have added many more cultivars since it reached the West in the mid-1800s. Crossing it with yellow flag (Iris pseudacorus) has produced yellow-flowered hybrids.
Conservation
- IUCN Red List
- NENot EvaluatedNot yet assessed
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