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Iris sibirica (Siberian iris)

The striking Siberian iris was first brought into cultivation in the Middle Ages, and is still widely grown in temperate regions.

Iris sibirica (Image: RBG Kew)

Species information

Scientific name: 

Iris sibirica L.

Common name: 

Siberian iris

Conservation status: 

National assessments according to IUCN Red List criteria: Vulnerable (VU) (Czech Republic, Hungary, Ukraine); Extinct in the Wild (EW) (Slovakia). Consider


Damp woodlands and grasslands.

Key Uses: 


Known hazards: 

All parts of both wild and cultivated Iris are poisonous, especially the rhizomes (swollen underground stems).


Sub class: 
Genus: Iris

About this species

The very attractive Siberian iris was first collected from the wild and planted in monasteries and royal gardens during the Middle Ages. The genus Iris was named after the Greek goddess of the rainbow, because of the wide variety of flower colours in this genus. The specific epithet sibirica refers to Siberia, where this species grows wild.


Discover more

Geography & Distribution

Siberian iris is native to central and eastern Europe, ranging from north-eastern Turkey, European Russia and western Siberia in the east, to northern Italy in the west. It has become naturalised in other temperate regions, such as the British Isles and North America.


Iris sibirica (Image: RBG Kew)

Iris sibirica has a rhizome (horizontal underground stem) and hollow, frequently branched, somewhat compressed vertical stems measuring 50—120 cm high. The leaves are green, and there are usually a few small ones on the stem in addition to several basal leaves measuring 25—80 cm x 4—10 mm. Each plant bears 1—3 (rarely 5), mid-blue to violet-blue (rarely white) flowers, measuring 5—7 cm in diameter. The pedicels measure up to 10 cm. The spathes (sheathing bracts) are brown and membranous at the time of flowering, and measure 2.5–5 cm. The perianth tube (formed by the petals and sepals) measures 4—7 mm. The falls (sepals of an iris) are 3—7 cm long, oblong to obovate (egg-shaped) and generally have a paler zone in the centre. The limbs (the expanded part of a corolla that has united petals) are obovate to orbicular in shape. The standard (the upper and usually largest petal) measures 2.5—6 x 1.2—2 cm, and is erect and narrowly obovate to elliptic. The style branches measure 3—4 x 0.5—0.8 cm and have erect, rounded to crenate lobes. The fruit is a capsule 2—4 cm long with an ellipsoidal to sub-cylindrical shape. The seeds are flat.

Flowers are borne between May and July, and the seeds ripen between August and September. The flowers are hermaphroditic (have both male and female organs) and are pollinated by insects. The plant is capable of self-fertilisation.

There are many cultivars of Siberian iris, and also hybrids with the blood iris (Iris sanguinea), ranging in flower colour from white to pale blue, dark blue, mauve and violet.

Threats & Conservation

Globally, Iris sibirica has an extensive range, and is likely to be of Least Concern according to IUCN Red List criteria, although this has not been verified by a formal conservation assessment.


Iris sibirica (Image: RBG Kew)

Iris sibirica grows well in moist or boggy ground and makes an attractive addition to the woodland garden or the margins of ponds and streams.

Millennium Seed Bank: Seed storage

Kew's Millennium Seed Bank Partnership aims to save plant life world wide, focusing on plants under threat and those of most use in the future. Seeds are dried, packaged and stored at a sub-zero temperature in our seed bank vault.

Description of seeds: Average 1,000 seed weight = 15.8 g.
Number of seed collections stored in the Millennium Seed Bank: Two.

This species at Kew

Siberian iris can be seen growing in the Rock Garden at Kew and the Iris Dell at Wakehurst.

A spirit-preserved specimen of Iris sibirica is held in the Herbarium, one of the behind-the-scenes areas of Kew. The details of this specimen can be seen on-line in the Herbarium Catalogue.

Kew at the RHS Chelsea Flower Show 2011

In 2011, Kew partnered with The Times to produce a show garden to showcase the significance of plants to science and society.

The garden, designed by Chelsea gold medallist Marcus Barnett, featured species chosen to demonstrate both beauty and utility, including medicinal, commercial, and industrial uses to underline the fact that plants are invaluable to our everyday lives – without them, none of us could live on this planet; they produce our food, clothing and the air that we breathe.

Iris sibirica is the wild relative of the cultivar Iris sibirica 'Dreaming Yellow', which is featuring in Kew’s garden at Chelsea. A cultivar is a cultivated variant of a species, which is often called a ‘variety’ in the horticultural trade. Cultivars usually have characteristics that make them more desirable to growers, for example a carrot that is sweeter than its wild relative or a rose with less thorns than its wild counterpart. 

- Find out more about the 2011 Chelsea Flower Show

- Browse some of the other plants that featured in the garden








References and credits

References and credits

Austin, C. (2005). Irises: A Gardener's Encyclopedia. Timber Press, Portland, Oregon.

British Iris Society Species Group (1997). A Guide to Species: Irises: Their Identification and Cultivation. Cambridge University Press, Cambridge.

Cooper, M.R. & Johnson, A.W. (1998). Poisonous Plants and Fungi in Britain. 2nd Edition. The Stationery Office, London.

Goldblatt, P. & Manning, J.C. (2008). The Iris Family: Natural History and Classification. Timber Press, Portland, Or.

Harris, J.G. & Woolf Harris, M. (2001). Plant Identification Terminology. Spring Lake Publishing, Spring Lake, Utah.

Köhlein, F. (1987). Iris. Helm, Bromley, Kent.

Kostrakiewicz, K. & Wroblewska, A. (2008). Low genetic variation in subpopulations of an endangered clonal plant Iris sibirica in southern Poland. Ann. Bot. Fennici 45: 186-194.

Mathews, B. (1984). Iris. In: Flora of Turkey Volume 8, ed. P.H. Davis. Edinburgh University Press, Edinburgh.

McEwen, C. (1996). The Siberian Iris. Timber Press, Portland, Oregon.

Royal Botanic Gardens Kew. (2008) Seed Information Database (SID). Version 7.1. Available from: (Accessed 19 January 2011).

Webb, D.A. & Chater, A.O. (1980). Iris. In: Flora Europaea Volume 5, ed. T.G. Tutin, V.H. Heywood, N.A. Burges, D.M. Moore, D.H. Valentine, S.M. Walters & D.A. Webb, pp. 87-92. Cambridge University Press, Cambridge.

Witkowski, Z.J., Król, W. & Solarz, W. (eds.) (2003). Carpathian List of Endangered Species. WWF and Institute of Nature Conservation, Polish Academy of Sciences, Vienna-Krakow.

Kew Science Editor: Anna Trias Blasi
Kew contributors: Steve Davis and Rui Fang (Sustainable Uses Group)
Copyediting: Emma Tredwell

While every effort has been taken to ensure that the information contained in these pages is reliable and complete, the notes on hazards, edibility and suchlike included here are recorded information and do not constitute recommendations. No responsibility will be taken for readers’ own actions. Full website terms and conditions.

Courses at Kew

Kew offers a variety of specialist training courses in horticulture, conservation and plant science.

Students learn about plant taxonomy and identification