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 has a short, thick, fleshy, greenish rhizomes,[4][5][6] which are 1–1.5 cm in diameter,[7] they are larger than other crested irises.[8] Underneath the rhizomes, are fleshy roots.[2][9][10] The rhizome is marked on top, with marks or scars of previous seasons leaves.[2][9][10] The rhizome produces lateral (non-flowering) shoots, these later become new growth points for the next season.[2][9][10] During the winter months, it goes dormant, the leaves die, leaving the rhizome bare on the soil surface.[11][12]
It has around 8,[2] basal leaves,[9][10][8] which are slightly glaucous,[2][11][13] yellowish green,[2][14] or greyish green,[7] or pale green.[13][15][16] They are sword-shaped,[7][16] they can grow up to between 30–60 cm (12–24 in) long and 2.5–7 cm (1–3 in) wide.[10][17] The leaves are visibly ribbed,[2][18][14] and change in size along the stem.[2][8][13]
They die away in the autumn,[3][11] to re-appear in the summer.[17]
It has slender,[12][5] stems that can grow up to between 30–90 cm (12–35 in) tall.[16][19][20] It has 2–4,[2][7] branches,[15][16][19] which are 15–20 cm (6–8 in) long.[7]
Iris milesii and Iris wattii are by far the tallest species of the crested irises group.[21]
The stems have several spathes (leaves of the flower bud), that are 2.5–3.8 cm (1–1 in) long,[7][13] and 2–2.5 cm (1–1 in) wide.[7]
The stems (and the branches) hold between 3 and 4 flowers,[7] in early summer,[4][12] between April and May,[7][11] or May to July.[2][9] They are short lived, but a continuous display can carry on for many weeks,[8][5] 8 to 10 weeks.[11]
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'.[8] The falls are reflexed,[4][23] obovate,[7] 3 cm long,[4] with a blade marked with dark purple, violet or lilac, lines, spots or mottled (streaks or blotches),[16][19][20] it has a finely fringed,[18] or toothed,[4] orange,[7][14][16] or white,[18][8] or yellow crest (or ridge).[5][13][20] The standards are narrowly obovate, 4–5 cm (2–2 in) long.[7][13] They are self-fertile.[2]
It has articulated pedicels, that are 2.5–4 cm (1–2 in) long.[7][13]
It has a small perianth tube, 1–1.5 cm long,[7][13] 2.5 cm long stamen, milky white anthers, 3 cm cylindric ovary.[7]
It has reddish purple, or lilac style branches, which are 3 cm long with deeply fringed (fimbriated) edges.[7][13]
After the iris has flowered, it produces an ovoid-globose,[7] or ovoid-cylindrical seed capsule,[2][9] between June and August.[7]
It is 2.8–3.3 cm (1–1 in) cm long,[9] with veining.[7] Inside the capsule, are pyriform (pear shaped) black brown seeds,[2][7] with a white aril.[7]
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.[11][24]
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.[25]
As most irises are diploid, having two sets of chromosomes, this can be used to identify hybrids and classification of groupings.[8] It has been counted several times, 2n=26, Simonet, 1932 and 2n=26, Chimphamba, 1973.[10]
It is normally published as 2n=26.[11][18][20]
The Latin specific epithetmilesii refers to Mr Frank Miles, who introduced it into cultivation in about 1880.[3][8][13][15] These plants were grown from seeds collected by his cousin in the Kulu district to the north of Simla.[3][8][13]
Flower buds of Iris milesii, from Himachal Pradesh, India.
Iris milesii is very hardy,[5][13][15] to between USDA Zone 3 and Zone 8,[22] or Zone 10.[29]
It is not hardy in the North Carolina climate, because it does not survive the winter.[21]
It is hardy in UK,[3][14] to −15 °C (or lower for short periods).[17] It is also hardy,[11] to Europe Zone H3,[4] although it still needs a sheltered position.[13]
It is tolerant of normal garden soil,[3] but prefers well drained,[11][5] sandy, peaty soils.[17][5] It does not like lime.[12]
It is tolerant of soils that are mildly acidic or mildly alkaline.[22]
It can also be propagated by division or by seed growing.[11][22]
Although the Iris can produce plenty to seed,[6] propagation via division is quicker and more reliable.[11]
Toxicity
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.[22]
