Perennials
Iris ensata
Japanese iris
Also known as: Japanese water iris · Japanese flag
Large, flattened flowers rise above narrow, upright leaves. This species-level listing is not a promise of a particular cultivar or flower color. Grow in rich, acidic soil near a moist garden edge.
At a glance
- Sun
- Full sun; tolerates partial shade
- Mature size
- 2–4 ft. tall × 18–24 in. wide
- Water
- Abundant summer moisture
- Hardiness
- USDA zones 4–9
- Bloom
- Summer; color varies with selection.
Sizes & prices
- #1$14.99
Catalog updated September 8, 2026. This is not a live stock count; please call to confirm availability and price.
Ask about this plantSelect a section to expand.
Resistance & tolerances
- Deer
- Resistant, not browse-proof.
- Drought
- Not a dry-site choice.
- Wet soil
- Tolerates summer wetness; saturated soil in winter can kill roots.
Resistance is not a guarantee; deer and rabbits may browse any plant.
Keep in mind: Harmful if eaten; sap can irritate skin. Wear gloves when dividing.
Seasonal interest
- Foliage
- Upright, strap-shaped leaves.
Growing & care
- Winter
- Keep roots out of standing water during dormancy.
- Division
- Divide after flowering when crowded, about every three years.
- Fall cleanup
- After a hard frost, remove old leaves, stems and nearby debris to reduce overwintering iris-borer eggs.
Sources & photo credits
University of Minnesota Extension
Image notes: Iris ensata, florawhite (CC BY4.0); resized
Reviewed September 21, 2026. Growing conditions vary by location.