This is a perennial beardless iris native to Asia from Siberia to Japan in the herbaceous perennial Iridaceae family. Japanese Irises prefer a sunny site but tolerate partial shade. They are best grown on water edges in damp, rich, acidic soil with abundant moisture during the growing season. They can even withstand periods of standing water, but in the winter plants do not tolerate saturated soil or standing water. For best results, remove the plants from the water garden in the fall, or plant rhizomes in pots about halfway in damp ground and then remove to dryer ground for the fall and winter. Blooms appear in mid-summer after bearded and Siberian irises. They produce a flatter flower of 3 to 6 inches with a foreshortened standard of one to several blooms on a stem up to 4 feet tall. Cultivars can be single or double in a variety of colors with striking markings. The rhizomes reproduce to create an increasing mass and should be divided about every three years after flowering has finished. New rhizomes can be planted in the spring or fall at about 1 to 2 inches deep and, unlike other irises, should be planted vertically with the growing tip pointed up. Japanese Iris make a showy presence in the garden and are excellent cut flowers. Insects, Diseases, and Other Plant Problems: More information on Iris .
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
Bulb; Herbaceous Perennial; Perennial; Poisonous; Water Plant
Life cycle
Perennial
USDA zones
4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b
Light
Full sun (6 or more hours of direct sunlight a day)
Soil texture
High Organic Matter
Soil pH
Acid (<6.0)
Soil drainage
Occasional Flooding | Occasionally Wet
Mature size
Height: 2 ft. 0 in. - 4 ft. 0 in. | Width: 1 ft. 6 in. - 2 ft. 0 in.
Maintenance
Medium
Canopy layer
4 - Herbaceous (3-15 ft)
Form & Appearance
Leaf color
Green
Leaf type
Sheath
Leaf shape
Lanceolate
Leaf margin
Entire
Leaf size
> 6 inches long
Hairs present
No
Leaf detail
Strap-like leaves are up to 24 inches tall in a knife shape
Flower color
Blue; Pink; Purple/Lavender; White
Flower value
Good Cut; Showy
Flower size
1-3 inches
Flower detail
Butterfly-like, 6-parted with 3 outer, spreading or pendent "falls" and 3 inner, erect "standards", with standards being smaller than the falls.
Bloom time
Summer
Fruit type
Capsule
Fruit size
< 1 inch wide
Wildlife & Ecology
Native status
Non-native
Origin
Asia, Siberia, Japan and Eastern Europe
Food & Medicine
Fruit type
Capsule
Uses (ethnobotany)
Water garden, borders, flower beds, cut flowers
Landscape Use
Landscape location
Naturalized Area; Patio; Small Space; Walkways
Landscape theme
Cutting Garden; Rain Garden; Water Garden
Design feature
Border; Mass Planting
Garden tags
#ncemgva2018 #showy flowers #water garden #full sun tolerant #deer resistant #poisonous #summer flowers #wet soils tolerant #cutting garden #flowers mid-summer #HS302 #problem for dogs #problem for cats #problem for horses #partial shade tolerant #HS304 #pond #contact dermatitis
Problems & Resistance
Insect problems
Slugs and Snails Found on Flowers and Foliage; Narcissus Bulb Fly; Potato Aphid on Ornamental Plants
Problems
Problem for Cats; Problem for Dogs; Problem for Horses
Resistant to
Deer; Diseases; Insect Pests; Wet Soil
Particularly resistant to
deer, wet soil; generally no diseases or insect pests
Propagation
Division
Poison severity
Low
Poison parts
Roots; Sap/Juice; Seeds
Poison symptoms
CAUSES ONLY LOW TOXICITY IF EATEN. SKIN IRRITATION MINOR, OR LASTING ONLY FOR A FEW MINUTES. Nausea, salivation, vomiting, abdominal pain, lethargy, diarrhea, elevated temperature following ingestion; skin irritation upon contact with seeds, rootstock, or cell sap.
Toxic principle
Pentacylic terpenoids (zeorin, missourin and missouriensin), Irisin, iridin, or irisine