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BogsHerbaceous Perennial

Iris ensata 'Kumo-no-obi'
  • RHS Plants for pollinators

Japanese water iris 'Kumo-no-obi'

A clump-forming perennial to 80cm in flower, erect, strap-like green leaves with a prominent midrib rise beneath upright stems bearing stately, large purple, single flowers with contrasting yellow centres, in summer

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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
Moisture
Poorly–drained, Moist but well–drained
pH
Acid, Neutral
Colour & scent
StemFlowerFoliageFruit
Spring Green
Summer Purple Yellow Green
Autumn Green
Winter
Position
  • Full sun
  • Partial shade
Aspect

South–facing or West–facing or East–facing

Exposure
Exposed or Sheltered
Hardiness
H6
Botanical details
Family
Iridaceae
Native to the UK
No
Foliage
Deciduous
Habit
Clump forming
Potentially harmful
Harmful if eaten. Wear gloves and other protective equipment when handling. Pets: Harmful if eaten. For further information and contact numbers regarding pets, see the HTA guide to potentially harmful plants
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

Accepted

How to grow

Cultivation

Grow in moist to wet, deep, humus-rich, acid soil, plant rhizomes 7.5cm deep; it thrives at the margins of ponds or streams, but avoid winter waterlogging

Propagation

Propagate by division of rhizomes after flowering from midsummer to early autumn every three years

Suggested planting locations and garden types
  • City and courtyard gardens
  • Cottage and informal garden
  • Wildlife gardens
  • Cut flowers
Pruning

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

Pests

May be susceptible to slugs, snails, iris thrip and iris sawfly

Diseases

May be susceptible to aphid-borne viruses, bacterial soft rot and grey moulds; see Iris diseases

Get involved

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