Iris pseudacorus
yellow iris
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
Other common names
yellow irisdaggers
see moreflagon
Jacob's sword
water flag
water skegs
yellow fleur-de-lis
Size
Ultimate height
1–1.5 metresTime to ultimate height
2–5 yearsUltimate spread
1–1.5 metresGrowing conditions
Moisture
Poorly–drainedpH
AcidColour & scent
| Stem | Flower | Foliage | Fruit | |
| Spring | Green | |||
|---|---|---|---|---|
| Summer | Yellow | Green | ||
| Autumn | ||||
| Winter |
Position
- Full sun
- Partial shade
Aspect
South–facing or East–facing
Exposure
Exposed or Sheltered Hardiness
H7Botanical details
- Family
- Iridaceae
- Native to the UK
- Yes
- Foliage
- Deciduous
- Habit
- Suckering
- 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
- Europe Africa Asia
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
- Coastal
- Cottage and informal garden
- City and courtyard gardens
- Flower borders and beds
- Wall side borders
Pruning
Remove any dying foliage in autumn, old flower stems can be cut down after flowering
Pests
Diseases
May be susceptible to aphid borne viruses, bacterial soft rot and grey moulds (Botrytis)
Get involved
The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.