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Herbaceous Perennial

Iris ensata

Japanese water iris

I. ensata is an herbaceous perennial to 80cm in height, forming a dense clump of erect foliage, with rich violet-purple flowers 10-12cm in width in mid summer, the broad, rounded falls each with a small white or yellow midrib

Other common names
Japanese flag
Japanese iris
see moresword-leaved iris
Synonyms
Iris kaempferi
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Size
Ultimate height
0.5–1 metres
Time to ultimate height
2–5 years
Ultimate spread
0.1–0.5 metres
Growing conditions
Clay
Loam
Sand
Moisture
Poorly–drained
pH
Acid
Colour & scent
StemFlowerFoliageFruit
Spring Green
Summer Purple Green
Autumn
Winter
Position
  • Full shade
  • Partial shade
Aspect

South–facing or East–facing or West–facing

Exposure
Exposed or Sheltered
Hardiness
H6
Botanical details
Family
Iridaceae
Native to the UK
No
Foliage
Deciduous
Habit
Clump forming
Potentially harmful
Ingestion may cause severe discomfort. Wear gloves and wash hands after handling
Genus

Iris may be rhizomatous or bulbous perennials, with narrow leaves and erect stems bearing flowers with 3 large spreading or pendent fall petals, alternating with 3 erect, often smaller, standard petals, in late winter, spring or early summer

Name status

Correct

Plant range
E Asia

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How to grow

Cultivation

Grow in moist to wet, deep, humus-rich, acid soil; it thrives at the margins of ponds or streams

Propagation

Propagate by division of rhizomes from midsummer to early autumn

Suggested planting locations and garden types
  • City and courtyard gardens
  • Coastal
  • Cottage and informal garden
  • Flower borders and beds
  • Wall side borders
Pruning

Remove any dying foliage in autumn, old flower stems can be cut down after flowering

Pests

May be attacked by slugs and snails

Diseases

Generally disease free

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