Iris latifolia (English iris)
Iris latifolia (Photo: Martyn Rix)
Iris latifolia (Mill.) Voss
English iris, Pyrenean flag
Not known to be threatened.
Damp mountain meadows.
All parts of both wild and cultivated Iris plants are poisonous, especially the rhizomes (swollen underground stems).
About this species
Iris latifolia is one of a group of about seven bulbous irises belonging to the subgenus Xiphium, found mainly in the Iberian Peninsula and western North Africa. Despite its common name, the English iris is native to France and Spain. Its flat leaves develop in spring, and the flowering stems, about 40 cm tall with two or three flowers, appear as the leaves die back. The flowers are deep purplish-blue, rarely pale blue or white, with upright standards and very round falls with a yellow stripe. Iris latifolia is one of the most long-lived species of Iris grown in Britain. One clump has been thriving by a river in Aberdeenshire for over 40 years, after being thrown out from a garden upstream. The British gardener and author Christopher Lloyd (1921-2006) grew English iris successfully in long grass in his meadow garden at Great Dixter House & Gardens in East Sussex.
Geography and distribution
Native to south-west France and north-west Spain (where it is found in the Pyrenees and Cantabrian Mountains).
Iris latifolia has an ovoid bulb, with fibrous tunics. The stem is 25–50 cm long. The lower leaves are 25–60 cm long, 5–10 mm wide and whitish on the upper surface. The leaves on the stem are narrower. Flowering occurs in late spring and summer. There are usually two flowers (sometimes three), which are deep purplish-blue. The falls are 60–75 mm long and 30–35 mm wide, with a yellow central stripe, with the wide limb tapering into the claw. The upright standards are 40–60 cm long, 15–20 mm wide and oblanceolate (spear-shaped and more pointed towards the base). The fruit is an elongated, beaked, pale brown capsule. The seeds are wrinkled.
Illustration from Curtis's Botanical Magazine
Curtis's Botanical Magazine (Editor: Martyn Rix) provides an international forum of particular interest to botanists and horticulturists, plant ecologists and those with a special interest in botanical illustration.
Now well over 200 years old, the Magazine is the longest running botanical periodical featuring colour illustrations of plants. Each four-part volume contains 24 plant portraits reproduced from watercolour originals by leading international botanical artists. Detailed but accessible articles combine horticultural and botanical information, history, conservation and economic uses of the plants described.
Published for the Royal Botanic Gardens, Kew by Wiley-Blackwell Publishing.
Why the ‘English’ iris?
The British taxonomist John Sims, wrote an article on Iris latifolia (at the time known as I. xiphioides) in Curtis’s Botanical Magazine in 1803, using the common name ‘Pyrenean flag’.
Sims explained that the name ‘English Iris’, commonly used by ‘the elder Botanists and even by the modern Florists, was acquired from the plant’s having been first introduced into the Low-Countries from England, most probably without any notice of its true habitat, and hence presumed a native of our country by those that received them; Clusius says, that on his first arrival here in 1571, he sought for it wild, until he was informed by Lobel of its being only cultivated in certain gardens near Bristol, where it had been most probably imported by some vessel from Spain or Portugal. Gerarde [sic] includes it among the British plants…but Parkinson was aware of its real habitat’.
Now, centuries later, English iris can indeed be found in the wild in Britain, as a garden escape and in naturalised colonies in grassy places and along roadsides.
Threats and conservation
There are no known threats to Iris latifolia, which occurs in several National Parks.
English iris is cultivated as an ornamental, for its attractive, deep blue flowers. There are also numerous cultivars with flowers varying in colour from purplish blue (for example Iris latifolia ‘Queen of the Blues’) to white (I. latifolia ‘Mont Blanc’).
Iris latifolia performs well when cultivated in long grass and moist meadow gardens.
This species at Kew
Iris latifolia is grown in the Woodland Garden (the area around the Temple of Aeolus) at Kew.
Alcohol-preserved and pressed and dried specimens of other species of Iris are held in Kew’s Herbarium, where they are available to researchers by appointment.
Huxley, A., Griffiths, M. & Levy, M. (eds) (1992). The New Royal Horticultural Society Dictionary of Gardening. Vol. 2 (D to K): 675. Macmillan Press, London.
Mathew, B. (1981). The Iris. Batsford, London.
Preston, C.D., Pearman, D.A. & Dines, T.A. (eds) (2002). New Atlas of the British and Irish Flora: An Atlas of the Vascular Plants of Britain, Ireland, the Isle of Man and the Channel Islands. CD-ROM. Oxford University Press, Oxford.
Sims, J. (1803). Iris xiphioides. Curtis’s Bot. Mag. 18: tab. 687.
World Checklist of Selected Plant Families (2010). The Board of Trustees of the Royal Botanic Gardens, Kew. Available online (accessed 28 March 2011).
Kew Science Editor: Martyn Rix
Kew contributors: Steve Davis (Sustainable Uses Group)
Copyediting: Emma Tredwell
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