Species Iris, Japanese Water Iris, Japanese Flag, Russian Iris
Iris ensata
Family: | Iridaceae (eye-rid-AY-see-ee) (Info) |
Genus: | Iris (EYE-ris) (Info) |
Species: | ensata (en-SA-tuh) (Info) |
Synonym: | Iris caricifolia |
Synonym: | Iris doniana |
Synonym: | Iris kaempferi |
Synonym: | Limniris ensata |

Class:
Japanese (JI)
Height:
24-36 in. (60-90 cm)
Spacing:
18-24 in. (45-60 cm)
Hardiness:
USDA Zone 5a: to -28.8 °C (-20 °F)
USDA Zone 5b: to -26.1 °C (-15 °F)
USDA Zone 6a: to -23.3 °C (-10 °F)
USDA Zone 6b: to -20.5 °C (-5 °F)
USDA Zone 7a: to -17.7 °C (0 °F)
USDA Zone 7b: to -14.9 °C (5 °F)
USDA Zone 8a: to -12.2 °C (10 °F)
USDA Zone 8b: to -9.4 °C (15 °F)
USDA Zone 9a: to -6.6 °C (20 °F)
USDA Zone 9b: to -3.8 °C (25 °F)
Sun Exposure:
Full Sun
Sun to Partial Shade
Danger:
Parts of plant are poisonous if ingested
Bloom Color:
Medium Purple
Bloom Time:
Very late (VLa)
Foliage:
Herbaceous
Other details:
Soil pH requirements:
6.1 to 6.5 (mildly acidic)
6.6 to 7.5 (neutral)
7.6 to 7.8 (mildly alkaline)
Patent Information:
Non-patented
Propagation Methods:
By dividing rhizomes, tubers, corms or bulbs (including offsets)
Seed Collecting:
N/A: plant does not set seed, flowers are sterile, or plants will not come true from seed
Awards (if applicable):
Foliage Color:
Bloom Characteristics:
Water Requirements:
Requires consistently moist soil; do not let dry out between waterings
Very high moisture needs; suitable for bogs and water gardens
Where to Grow:
Regional
This plant is said to grow outdoors in the following regions:
Canoga Park, California
Fremont, California
Huntington Beach, California
Merced, California
Sacramento, California
San Leandro, California
Santa Maria, California
Barbourville, Kentucky
Bath, Maine
Jamaica Plain, Massachusetts
Blue Springs, Missouri
Neptune, New Jersey
Buffalo, New York
Southold, New York
Mount Gilead, North Carolina
MOUNT HOOD PARKDALE, Oregon
Tangent, Oregon
Wilkes Barre, Pennsylvania
Coppell, Texas
Port Lavaca, Texas
show allGardeners' Notes:
Rating | Content |
---|---|
Positive | On Feb 20, 2015, coriaceous from ROSLINDALE, MA wrote: Japanese iris are hardy in Z4, some say Z3. |
Positive | On Mar 21, 2011, annlof from Camarillo, CA wrote: Iris ensata blooms for a short period in midsummer. Some cultivars have flowers as big as dinner plates, and some are a true vivid blue -- absolutely stunning! It's probably one of the last irises to bloom (early July in New England.) This iris thrives in bogs but also does quite well in a sunny border with good, deep loam. |
Positive | On Jul 29, 2006, ladyannne from Merced, CA (Zone 9a) wrote: We place these in pots, cover with large rocks and pop them in our ponds and waterfalls. Reliable, startling early spring colour. I collected the seeds this year, and will be experimenting with them. |