Iris longipetala is a species in the genus Iris, it is also in the subgenus Limniris and in the series Longipetalae. It is a rhizomatousperennial, from North America. It has dark green or bluish green, grass-like leaves, small stem and 3–8 flowers, that range from creamy-white, pale blue to lavender blue. It is cultivated as an ornamental plant in temperate regions.
Description
Iris longipetala has a rhizome, with small trailing branches and plenty of fleshy toots. The spreading rhizomes give the appearance of a clump forming plant. It can form dense colonies. It has a small stem, which reaches a height of between, with a few branches and is about 3–6 cm in diameter. The stem has 3 leaves along it, which overlap and wrap around the stem. The leaves can be either dark green or bluish green and they can be equal or just shorter than the flowering stems. They start at the base of the plant, rising up with a grass-like form. They are generally, between 5-11mm wide. They are briefly deciduous, turning grey or yellow-brown when dying. Before soon re-appearing, giving the plant an evergreen appearance. It can have between 3–8 flowers per stem, in spring,, or summer. The lilac-purple perianth tube is between 3–8 cm in length. The flowers are large, measuring about across, but with narrow petals. The very lightly scented flowers, come in a range of shades from creamy-white, pale blue, to lavender blue. Each flower has a purple veining. The falls often have a slight yellowish signal patch. The flowers have 2-lobed stigmas. After flowering, it has a seed capsule that is narrowed at each end. The capsule has 6 ribs along it length. It is almost round in cross-section. Inside are wrinkled dark brown globular seeds, which are pyriform.
Biochemistry
As most irises are diploid, having two sets of chromosomes. This can be used to identify hybrids and classification of groupings. It has a chromosome count : 2n=86, 88,.
It is spread over the coastal grasslands in moist open spaces. It is also found in grazed pastures. At altitudes at less than above sea level.
Cultivation
It is hardy to USDAZone 3, which is not hardy below 10 degrees F. It can be planted in sun or part shade, it tolerates full sun in coastal areas and a little shade inland with regular watering through the blooming period. It requires less water after the flowering period has ended. It prefers soils with good drainage. It will survive a long period of summer dryness except in hot inland areas. It is deer resistant, and it also cattle resistant, due to the foliage being unpalatable. It can tolerate wet heavy soils including clay. It is suitable to be cultivated in garden borders, the fringes of shrubberies in soils with sandy loam. It may also suitable for pond margins or bog gardens. Specimens can be found at the Royal Botanic Garden Edinburgh. Aulacorthum solani and Rhapalosiphonius staphyleae are two aphids that can be found on the plant.
Propagation
It is better propagated by means of 'division'.
Hybrids and cultivars
Iris longipetala hybridizes readily with Iris missouriensis. A known hybrid is Iris longipetala superba, A known variant is Iris longipetala var. pelogonus. But this could be a version of Iris missouriensis var. pelogonus which is a synonym of Iris missouriensis.
Toxicity
Like many other irises, most parts of the plant are poisonous, if mistakenly ingested can cause stomach pains and vomiting. Also handling the plant may cause a skin irritation or an allergic reaction.
