Iris ruthenica, sometimes called ever blooming iris (in the UK), Russian iris, pilgrim iris and Hungarian iris (in Europe), is a species in the genus Iris- subgenus Limniris. It is a rhizomatous perennial, with a wide distribution, ranging from eastern Europe to Central Asia. It has grass-like leaves, thick stem and violet or bluish lavender flowers which are marked with violet veining.
Iris ruthenica is very variable and hybrids can look very similar to Iris uniflora. The other species in the Iris series Ruthenicae. It can be variable with its leaf length and width, and flower height.
It has bright green leaves, or greyish green leaves. That are tall and thin, and grass-like, measuring between 10 – 40 cm (8–13 in) long and 2 – 6 mm wide. The leaves can grow longer than the flower stem.
The large flowers are between 3–5 cm in diameter, with a cylindrical, perianth tube measuring 0.5–1.5 cm long. The flowers come in a range of blue shades between violet  and bluish lavender. Which are marked with violet veining. Like other irises, it has 2 pairs of petals, 3 large sepals (outer petals), known as the 'falls' and 3 inner, smaller petals (or tepals), known as the 'standards'. The falls (measuring 4.5–5 cm) are white. The standards (measuring 4–6 cm) are almost erect. The bracts (measuring 3–5 cm ) are greenish with pink margins, violet blue stigma, and milky white anthers.
It has a globose (globe-like) to ovoid shaped seed capsule (measuring 1.2—1.5 cm) in June–August (after the flowering period is over). Once they are ripe, the seed capsules fully open and all the seeds are dispersed in one movement. Unlike other iris species. The seeds are pyriform (pear-shaped) and have an aril (white appendage on the edge of the seed). The aril disappears soon after and shrivels up.
As most irises are diploid, having two sets of chromosomes. Which can be used to identify hybrids and classification of groupings. It has a chromosome count: 2n=84  (found by Simonet in 1934).
It has several common names; 'ever blooming iris' (in the UK), 'Russian Iris', 'pilgrim iris' (sometimes called a synonym of Iris ruthenica), and 'Hungarian Iris' in Europe.
Iris ruthenica was first published by John Bellenden Ker Gawler in Botanical Magazine in 1808. It was later published in 1811, as Iris ruthenica with the common name 'Pigmy iris' in Curtis's Botanical Magazine, vol. 34, table 1393. Pigmy iris is now used as the common name of Iris pumila.
Distribution and habitat
It is found in southern Russia and Siberia, through Central Asia, (including Altai Mountains and Turkestan, on the Tien Shen mountain range, Kazakhstan and Mongolia), to China and Korea. Within Europe, it is found in Romania.
It is listed with Iris bloudowii, Iris humilis, Iris lactea, Iris sibirica, Iris tenuifolia and Iris tigridia as being found in the Altai-Sayan region (where Russia, China, Mongolia and Kazakhstan come together).
It is found on dry meadows (including grass plains and steppes), pine and birch forest edges and edges of woodland. It can also be found in forest clearings in the forest-meadow mountain belt. Forming a thicket ground-cover.
In Mongolia it is found under Pinus sylvestris/Betula platyphylla subtaiga forests, in montane meadow steppes with Festuca lenensis and Artemisia sericea and in Pinus sibirica/Picea obovata dark taiga forests (within the upper montane belt with Rubus saxatilis and Lathyrus humilis).
On the Altai Mountains, it is found with other mountain flowers including Siberian Dogs-tooth Violet (Erythronium krylovii), Altai Foxtail Lily (Eremurus), a variety of saxifrages, Aquilegia, Gentiana grandiflora, Papaver nudicaule and the yellow Iris bloudowii.
Iris ruthenica does not flower very well in the UK. It is best cultivated in fertile soils that do not dry out. It is best suited for Rock Gardens or at the front of a flower border. Although sinks or troughs could be used. It also grows well on dry peat banks. It is tolerant of semi-shade, but prefers full sun.
Iris ruthenica is grown in several Russian botanical gardens including, Barnaul, Ivanovo, Irkutsk, Kirov, Moscow, Rostov-on-Don, St. Petersburg, Stavropol, Tomsk, Omsk, Novosibirsk and Chita.
It can be propagated by division or by seed. The seeds should be sown in the autumn and the rhizomes divided in early spring. The seeds germinate fairly quickly and new plants are easily raised. But the young plants must not dry out. The old and damaged rhizomes should be removed before replanting.
Hybrids and cultivars
Iris ruthenica has the following known cultivars;
- "Iris ruthenica Ker Gawl. is an accepted name". theplantlist.org. 23 March 2012. Retrieved 5 November 2014.
- "FOC Vol. 24 Page 303". efloras.org. Retrieved 5 November 2014.
- "Iris ruthenica". encyclopaedia.alpinegardensociety.net. Retrieved 6 November 2014.
- Alekseeva, Nina (2007). "Iris ruthenia". flower.onego.ru. Retrieved 6 November 2014.
- Owen, Toni. "The Differences Between Iris Reticulata & Ruthenica". homeguides.sfgate.com. Retrieved 5 November 2014.
- James Cullen, Sabina G. Knees and H. Suzanne Cubey (Editors) The European Garden Flora Flowering Plants: A Manual for the Identification, p. 251, at Google Books
- "Iris ruthenica". navigate.botanicgardens.org. Retrieved 5 November 2014.
- Austin, Claire. "Irises A Garden Encyclopedia" (PDF). worldtracker.org. pp. 274–275, 287. Retrieved 5 November 2014.
- Komarov, V.L. (1935). "Akademiya Nauk SSSR (FLORA of the U.S.S.R.) Vol. IV". Retrieved 9 October 2014.
- "Iris ruthenica". hih-gruppen.se. Retrieved 5 November 2014.
- Kramb, D. (10 November 2003). "Iris ruthenica". signa.org (Species Iris Group of North America). Retrieved 5 November 2014.
- William Robinson Hardy Flowers , p. 152, at Google Books
- Cassidy, George E.; Linnegar, Sidney (1987). Growing Irises (Revised ed.). Bromley: Christopher Helm. p. 146. ISBN 978-0-88192-089-5.
- Austin, Claire. "Irises A Garden Encyclopedia" (PDF). worldtracker.org. pp. 274–275. Retrieved 29 October 2014.
- Dykes, William (2009). "Handbook of Garden Irises" (PDF). beardlessiris.org (The Group for Beardless Irises). Retrieved 5 November 2014.
- Karol Marhold (ed.). "IAPT/IOPB chromosome data 9" (PDF). iopb.org. Retrieved 5 November 2014.
- Laurin, Terry (10 January 2014). "(SPEC) Iris ruthenica Ker-Gawl". wiki.irises.org. Retrieved 5 November 2014.
- "Iris ruthenica". nciku.com. Retrieved 5 November 2014.
- "page 68". forgottenbooks.com. Retrieved 5 November 2014.
- "Ever blooming Iris". rhs.org.uk (Royal Horticultural Society). Retrieved 5 November 2014.
- Aleksandr Leonidovich Kovalevsk (Editor)Biogeochemical Exploration for Mineral Deposits, p. 70, at Google Books
- Elizabeth Lawrence A Rock Garden in the South , p. 76, at Google Books
- "Iris ruthenica". Germplasm Resources Information Network (GRIN). Agricultural Research Service (ARS), United States Department of Agriculture (USDA). Retrieved 30 April 2015.
- Barker, C; Govaerts, R. "Iris ruthenica Ker Gawl., Bot. Mag. 28: t. 1123 (1808)". apps.kew.org. Retrieved 5 November 2014.
- William Jackson Hooker The Botany of Captain Beechy's Voyage, p. 396, at Google Books
- Sergeĭ Kirillovich Cherepanov Vascular Plants of Russia and Adjacent States (the Former USSR) , p. 280, at Google Books
- Mark V Lomolino, Dov F. Sax and James H Brown (editors)Foundations of Biogeography : Classic Papers with Commentaries Parts 1–4, p. 475, at Google Books
- "THE ALTAI, CENTRAL ASIA'S GOLDEN MOUNTAINS". greentours.co.uk. Retrieved 5 November 2014.
- "Biodiversity of Altai-Sayan Ecoregion". bioaltai-sayan.ru. Retrieved 15 August 2015.
- Dalamsuren, Choimaa; Hauck, Markus; Muhlenberg, Michael (7 January 2005). "Vegetation at the Taige forst steppe borderline in Western Khentey Mountains, Northern Mongolia" (PDF). sekj.org (Finnish Zoological and Botanical Publishing Board). p. 415. Retrieved 5 November 2014.
- Folke Andersson (editor) Coniferous Forests , p. 72-73, at Google Books
- Ivanova1, G. A.; Ivanov, V. A.; Kukavskaya, E. A.; Soja, A. J. (27 January 2010). "The frequency of forest fires in Scots pine stands of Tuva, Russia". iopscience.iop.org. Retrieved 5 November 2014.
- Stebbings, Geoff (1997). The Gardener's Guide to Growing Irises. Newton Abbot: David and Charles. p. 18. ISBN 978-0715305393.
- "Iris ruthenica var nana". rhs.org.uk. Retrieved 5 November 2014.
- "Iris ruthenica - Ris Ruthenia, Iris Belarusian". nature.jardin.free.fr. Retrieved 5 November 2014.
- "Iris ruthenica subsp. brevituba (Maxim.) Doronkin is an accepted name". theplantlist.org. 23 March 2012. Retrieved 5 November 2014.
- "RE: Iris runthenic". hort.net. 30 May 2010. Retrieved 6 November 2014.
- "IRIS PHOTO GALLERY". hootowlhollow.com. Retrieved 6 November 2014.
- Aldén, B., S. Ryman & M. Hjertson. 2009. Våra kulturväxters namn – ursprung och användning. Formas, Stockholm (Handbook on Swedish cultivated and utility plants, their names and origin).
- Czerepanov, S. K. 1995. Vascular plants of Russia and adjacent states (the former USSR).
- Khassanov, F. O. & N. Rakhimova. 2012. Taxonomic revision of the genus Iris L. (Iridaceae Juss.) for the flora of Central Asia. Stapfia 97:175.
- Komarov, V. L. et al., eds. 1934–1964. Flora SSSR.
- Mathew, B. 1981. The Iris. 83.
- Tutin, T. G. et al., eds. 1964–1980. Flora europaea.
- Waddick, J. W. & Zhao Yu-tang. 1992. Iris of China.