Iris delavayi is a species of flowering plant in the subgenus Limniris and in the series Sibiricae of the family Iridaceae.

[2] It has stout, creeping rhizomes (about 1 cm in diameter), that create clumps or tufts of plants.

[7][8][10] It has a hollow, 1–3 branched flowering stem that grows up to between 60–150 cm (24–59 in) long and 5–7 mm wide.

[8][10] The spathes surround 2 flowers (per stem branch), borne in early summer,[3][5][10][15] between May and August (or June or July in the UK).

[3][4][5][7][10][11][12][13][14][15] The smaller standards are held at an oblique angle, measuring 5.5 cm long and oblanceolate (in from).

[3] Inside are semi-orbicular, flat, (disc like) reddish brown seeds, with are about 6 mm in diameter.

[3] In 2011, the iris has been studied to work out its iridal properties from specimens collected in the north-western Yunnan Province of China, eight iridal-type triterpenoids were isolated, three of which were new.

Both 2(7)Z- and 2(7)E-iridals were isolated in about equal amounts from the sample collected at Laojunshan, while only 2(7)Z-iridals were isolated from samples collected in Shangrila area, indicating the presence of chemical diversity in the species.

[9] It is written as 长葶鸢尾 in Chinese script and known as chang ting yuan wei in China.

Plants were then raised by Micheli,[11] who then first published and described the iris in Revue Horticole (résumé de tout ce qui parait d'intéressant en jardinage, of Paris) Vol.

[6] On 1 June 1899, Sir Joseph Dalton Hooker wrote about the iris in Curtis's Botanical Magazine, Tab.

[11] The authors of the 'Flora of China' have speculated that the early found specimens of Iris laevigata Fisch.

[19] This plant has gained the Royal Horticultural Society's Award of Garden Merit.

[14] The Sino-siberian irises all generally have similar cultivation requirements with minor alterations.

[6] Iris delavayi will tolerate temperatures of up to −15 degrees C.[7] But may survive lower if protected or well mulched in winter.

[16] They can be divided after flowering (in early summer) or autumn (in the UK[4]) if the clumps become too big and congested.

[11] Iris delavayi crosses also include; 'Berliner Riesen', 'Black Pirate', 'Delfor', 'Diamond Jubilee', 'Diomed', 'Far Voyager', 'Fifinella', 'Lightly Touched', 'Normal', 'Ormonde', 'Persimmon'.

[29] Like many other irises, most parts of the plant are poisonous (rhizome and leaves), if mistakenly ingested can cause stomach pains and vomiting.