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Iris pseudacorus

yellow iris

RHS Plant Shop from £8.99 Sold by 53 nurseries

  • Other common names yellow iris
    daggers

    flagon
    Jacob's sword
    water flag
    water skegs
    yellow flag
    yellow fleur-de-lis

    see more

  • Family Iridaceae

  • 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

  • Details I. pseudacorus is a vigorous herbaceous perennial forming extensive colonies to 1.5m in height, with bright yellow flowers up to 10cm in width, the falls with brown veining in the centre, in mid and late summer

  • Plant range Europe Africa Asia

Characteristics

  • Foliage Deciduous

  • Habit Suckering

  • Toxicity Ingestion may cause severe discomfort. Wear gloves and wash hands after handling

  • Hardiness

    Hardiness ratings

    All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets

    • H1a - Under glass all year (>15C)
    • H1b - Can be grown outside in the summer (10 - 15)
    • H1c - Can be grown outside in the summer (5 - 10)
    • H2 - Tolerant of low temperatures, but not surviving being frozen (1 to 5)
    • H3 - Hardy in coastal and relatively mild parts of the UK (-5 to 1)
    • H4 - Hardy through most of the UK (-10 to -5)
    • H5 - Hardy in most places throughout the UK even in severe winters (-15 to -10)
    • H6 - Hardy in all of UK and northern Europe (-20 to -15)
    • H7 - Hardy in the severest European continental climates (< -20)

    H7

Colour

Sunlight

  • Full Sun

  • Partial Shade

  • Aspect South-facing or East-facing

  • Exposure Exposed or Sheltered

Soil

  • Clay

    Clay

  • Loam

    Loam

  • MoisturePoorly-drained

  • SoilClay, Loam

  • pHAcid

Size

  • Ultimate height 1-1.5 metres

  • Ultimate spread 1-1.5 metres

  • Time to ultimate height 2-5 years

How to grow

Cultivation Grow in wet, deep, acid, humus-rich soil in full sun or partial shade. It thrives at the margins of large ponds or streams; vigorous so site with care

Propagation Propagate by division from midsummer to early autumn, plant immediately in flowering positions

Suggested planting locations and garden types Flower borders and beds Wall-side Borders Coastal Cottage & Informal Garden City & Courtyard Gardens

How to care

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

Pests May be attacked by slugs, snails and thrips

Diseases Susceptible to aphid borne viruses, bacterial soft rot and Botrytis

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RHS Plants Shop

Iris pseudacorus

yellow iris

Buy from £8.99 at the RHS Plants Shop

Buy from £8.99 at the RHS Plants Shop

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