Iris milesii (also known as the red flower iris) is a plant species in the genus Iris, subgenus Limniris and in the section Lophiris (crested irises). It is a rhizomatous, beardless perennial plant, native to the Himalayas, India and China. It has pinkish-violet, or pinkish purple, or pinkish-lavender or pinkish lilac flowers, with a fringed yellow or orange crest (or ridge). It is cultivated as an ornamental plant in temperate regions.
It is similar in form to Iris tectorum (another crested iris).[1] [2]
It has a short, thick, fleshy, greenish rhizomes,[3] [4] [5] which are 1–1.5 cm in diameter, they are larger than other crested irises.[6] Underneath the rhizomes, are fleshy roots.[1] [7] The rhizome is marked on top, with marks or scars of previous seasons leaves.[1] [8] [7] The rhizome produces lateral (non-flowering) shoots, these later become new growth points for the next season.[1] [8] [7] During the winter months, it goes dormant, the leaves die, leaving the rhizome bare on the soil surface.[9] [10]
It has around 8,[1] basal leaves,[8] [7] [6] which are slightly glaucous,[1] [9] [11] yellowish green,[1] [12] or greyish green,[13] or pale green.[11] [14] [15] They are sword-shaped,[13] [15] they can grow up to between 30- long and 2.5- wide.[7] The leaves are visibly ribbed,[1] [16] [12] and change in size along the stem.[1] [6] [11] They die away in the autumn,[2] [9] to re-appear in the summer.[17]
It has slender,[10] [4] stems that can grow up to between 30- tall.[15] [18] [19] It has 2–4,[1] [13] branches,[14] [15] [18] which are 15- long.[13]
Iris milesii and Iris wattii are by far the tallest species of the crested irises group.[20]
The stems have several spathes (leaves of the flower bud), that are 2.5- long,[13] [11] and 2- wide.[13]
The stems (and the branches) hold between 3 and 4 flowers,[13] in early summer,[3] [10] between April and May,[13] [9] or May to July.[1] [8] They are short lived, but a continuous display can carry on for many weeks,[6] [4] 8 to 10 weeks.[9]
The flowers are 6- in diameter,[5] [11] [15] they are smaller than Iris japonica,[10] and Iris tectorum.[2] [9] The flowers come in shades of pinkish-violet,[1] [8] or pinkish purple,[2] [11] [21] or pinkish lilac,[3] [11] [22] pinkish-lavender,[16] [15] or pale mauve.[5] [18]
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'.[6] The falls are reflexed,[3] [22] obovate,[13] 3 cm long,[3] with a blade marked with dark purple, violet or lilac, lines, spots or mottled (streaks or blotches),[15] [18] [19] it has a finely fringed,[16] or toothed,[3] orange,[13] [12] [15] or white,[16] [6] or yellow crest (or ridge).[4] [11] [19] The standards are narrowly obovate, 4- long.[13] [11] They are self-fertile.[1]
It has articulated pedicels, that are 2.5- long.[13] [11]
It has a small perianth tube, 1–1.5 cm long,[13] [11] 2.5 cm long stamen, milky white anthers, 3 cm cylindric ovary.[13]
It has reddish purple, or lilac style branches, which are 3 cm long with deeply fringed (fimbriated) edges.[13] [11]
After the iris has flowered, it produces an ovoid-globose,[13] or ovoid-cylindrical seed capsule,[1] [8] between June and August.[13]
It is 2.8- cm long,[8] with veining.[13] Inside the capsule, are pyriform (pear shaped) black brown seeds,[1] [13] with a white aril.[13]
In May 1984, a study was carried out on the rhizomes of Iris milesii, to ascertain their chemical constituency. Several isoflavones (chemical compounds) were found.[9] [23]
In December 1884, a further study was carried out on the rhizomes of Iris milesii and Iris kemaonensis (under old spelling 'kumaonensis'). It found several isoflavones in both rhizomes.[24]
Tetrahydroxy-3'-methoxyisoflavone (C16H12O7) can be found naturally within the iris,[25] rhizomes.[26]
As most irises are diploid, having two sets of chromosomes, this can be used to identify hybrids and classification of groupings.[6] It has been counted several times, 2n=26, Simonet, 1932 and 2n=26, Chimphamba, 1973.[7] It is normally published as 2n=26.[9] [16] [19]
It has the common names of red-flower iris,[8] [21] and waterbird iris (in Australia).[22] [27]
It is written as 红花鸢尾 in Chinese script,[13] and known as hong hua yuan wei in Pidgin in China.[13]
The Latin specific epithet milesii refers to Mr Frank Miles, who introduced it into cultivation in about 1880.[2] [6] [11] [14] These plants were grown from seeds collected by his cousin in the Kulu district to the north of Simla.[2] [6] [11]
It was first published and described by Michael Foster in Gardeners' Chronicle Volume 20 page 231 in 1883.[13] [28] John Gilbert Baker also described the iris in Curtis's Botanical Magazine Volume 112, tab.6889 in 1886.[11]
It was verified by United States Department of Agriculture and the Agricultural Research Service on 9 January 2003 and then updated on 1 December 2004.
Iris milesii is an accepted name by the RHS.[15]
Iris milesii is native to temperate and tropical regions of Asia,[20] [27] [28]
It is found in temperate Asia, within the Chinese provinces,[10] [28] of Sichuan, Xizang and Yunnan.[13] [9]
It is also found in tropical Asia, within the States and union territories of India, in Himachal Pradesh,[16] Uttar Pradesh,[17] Jammu and Kashmir.[9] [17] It is also thought to be found in Tibet.[28]
It grows in the conifer forest margins of hillsides,[9] [17] [18] in meadows,[9] in open groves (and clearings),[18] and wet valleys.[13] [16]
They can be found at an altitude of 1500- above sea level.[9] [17]
They are 'abundant' in the wild.[16]
Iris milesii is very hardy,[4] [11] [14] to between USDA Zone 3 and Zone 8,[21] or Zone 10.[27] It is not hardy in the North Carolina climate, because it does not survive the winter.[20] It is hardy in UK,[2] [12] to −15 °C (or lower for short periods).[17] It is also hardy,[9] to Europe Zone H3,[3] although it still needs a sheltered position.[11]
It is tolerant of normal garden soil,[2] but prefers well drained,[9] [4] sandy, peaty soils.[17] [4] It does not like lime.[10] It is tolerant of soils that are mildly acidic or mildly alkaline.[21]
It prefers a sunny[17] [14] [21] or semi-shade position.[4] [5] [27]
It also has average water needs.[9] [21] It prefers to have moisture during the growing season, but it will not survive in waterlogged sites/[16]
It can be grown in mixed flower border,[9] [12] [5] or rock gardens.[9]
It does suffer virus problems that Iris tectorum.[9]
It is not rarely found in cultivation.[16] [17] [4] [20]
It can also be propagated by division or by seed growing.[9] [21]
Although the Iris can produce plenty to seed,[5] propagation via division is quicker and more reliable.[9]
Like many other irises, most parts of the plant are poisonous (rhizome and leaves), if mistakenly ingested can cause stomach pains and vomiting. Also handling the plant may cause a skin irritation or an allergic reaction.[21]