Iris sibirica
Siberian flag
A rhizomatous herbaceous perennial up to 1.2m tall, with narrow grassy foliage and branched stems bearing up to 5 violet-blue flowers 6-7cm wide in early summer, the falls veined purple on white at the base
Size
Ultimate height
1–1.5 metresTime to ultimate height
2–5 yearsUltimate spread
0.1–0.5 metresGrowing conditions
Moisture
Moist but well–drainedpH
Acid, Alkaline, NeutralColour & scent
| Stem | Flower | Foliage | Fruit | |
| Spring | Green | |||
|---|---|---|---|---|
| Summer | Blue Purple | Green | ||
| Autumn | Green | |||
| Winter |
Position
- Full sun
- Partial shade
Aspect
West–facing or East–facing or South–facing
Exposure
Exposed or Sheltered Hardiness
H7Botanical details
- Family
- Iridaceae
- Native to GB / Ireland
- No
- Foliage
- Deciduous
- Habit
- Bushy
- 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
Correct
- Plant range
- Europe to C Asia
How to grow
Cultivation
Grow in any good garden soil that is preferably moist but not waterlogged. In drier soils, dig in well-rotted organic matter before planting then apply as a mulch each spring
Propagation
Propagate by seed or 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
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; see Iris diseases
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.