(Wall. ex Nees) T. Anders. ex Benth.
Kurinji or Neelakurinji (Strobilanthes kunthianus) is a shrub that is found in the shola forests of the Western Ghats in South India. Nilgiri Hills, which literally means the blue mountains, got their name from the purplish blue flowers of Neelakurinji that blossoms only once in 12 years. Of all long interval bloomers (or plietesials) Strobilanthes kunthianus is the most rigorously demonstrated, with documented bloomings in 1838, 1850, 1862, 1874, 1886, 1898, 1910, 1922, 1934, 1946, 1958, 1970  1982, 1994, and 2006  The species is known as ನೀಲಕುರಂಜಿ in Kannada, குறிஞ்சி in Tamil, and നീലകുറിഞ്ഞി in Malayalam.
Some Kurinji flowers bloom once every seven years, and then die. Their seeds subsequently sprout and continue the cycle of life and death.
Kurinji grows at an altitude of 1300 to 2400 metres. The plant is usually 30 to 60 cm high. They can, however, grow well beyond 180 cm under congenial conditions.
The Kurinji plant belongs to the genus Strobilanthes which was first scientifically described by Christian Gottfried Daniel Nees von Esenbeck in the 19th century. The genus has around 250 species, of which at least 46 are found in India. Most of these species show an unusual flowering behavior, varying from annual to 16-year blooming cycles.
Blooming periods of different species of Kurinji differ from each other. Plants that bloom at long intervals like Strobilanthes kunthianus are known as plietesials. Other commonly used expressions or terms which apply to part or all of the plietesial life history include gregarious flowering, mast seeding and supra-annual synchronized semelparity (semelparity = monocarpy).
Some species of Strobilanthes are examples of a mass seeding phenomenon termed as masting which can be defined as "synchronous production of seed at long intervals by a population of plants". Strict masting only occurs in species that are monocarpic (or semelparous) -- individuals of the species only reproduce once during their lifetime, then die, as is the case with Strobilanthes kunthianus.
Kurinji once used to cover the Nilgiri Hills and Palani Hills like a carpet during its flowering season. Now plantations and dwellings occupy much of their habitat. Besides the Western Ghats, Neelakurinji is also seen in the Shevroys in the Eastern Ghats, Anamalai hills Idukki district andand Agali hills in Palakad in Kerali and sandur hills of Bellary district in Karnataka. In 2006, Neelakurunji flowered again in Kerala and Tamil Nadu after a gap of 12 years. Thereafter, the Strobilanthes cuspidatus species of Kurinji flowers were found blooming in 2016 in Udhagamandalam near a major road.
Kurinjimala Sanctuary protects the kurinji in approximately 32 km² core habitat in Kottakamboor and Vattavada villages in Idukki district of Kerala, The Save Kurinji Campaign Council organizes campaigns and, programs for conservation of the Kurinji plant and its habit. Kurinji Andavar temple located in Kodaikanal on Tamil Nadu dedicated to Hindu God Kartikeya also preserves Strobilanthes plants.
References in literature
Kurinji flower is used to describe the associated mountainous landscape where it blooms in classical Tamil literature. The famous poetic fragment "Red Earth and Pouring Rain" from Tamil literary piece Kuruntokai makes an indirect reference to the flower. The historical novel, Kurinji Flowers by Clare Flynn features the neelakurinji as a backdrop to a tragic love affair in 1940s India.
- Burley and Styles, editors (1976). Tropical Trees. London: Academic Press. pp. 138–139.
- Frontline (India) Vol. 23 # 17 (August 26, 2006)
- "Wonder flower in bloom again". The Hindu. 14 November 2016. Retrieved 14 November 2016.
- Mike Kielty, Thursday Online, The Lost Gardens of the Raj (2008-3-4)
- Save Kurinji Campaign,  Flower of the blue mountains]
- Kurinji crown - The Palni Hills are once again witnessing the mass flowering of neelakurinji; TEXT & PHOTOGRAPHS by IAN LOCKWOOD; Volume 23 - Issue 17 :: Aug. 26-Sep. 08, 2006; Frontline Magazine; INDIA'S NATIONAL MAGAZINE from the publishers of THE HINDU
- Daniel, Thomas F. 2006. Synchronous Flowering and Monocarpy Suggest Plietesial Life History for Neotropical Stenostephanus chiapensis (Acanthaceae). Proceedings of the California Academy of Sciences. Fourth Series. Volume 57, No. 38, pp. 1011–1018, 1 fig. December 28, 2006
- Kelly, D. 1994. The evolutionary ecology of mast seeding (PDF). Trends Ecol. Evol.. 9(12): 465-470. Accessed on 24 January 2010
- Janzen (1976) in Annul. Rev. Ecol. Syst., 7, 347-391
- Strobilanthes callosus; Botany Photo of the Day; Notes posted by Daniel Mosquin; January 13, 2009
- Flynn, Clare (8 October 2014). Kurinji Flowers. London: Cranbrook Press.
- Sharma, MV et al. 2008. Reproductive strategies of Strobilanthes kunthianus, an endemic, semelparous species in southern Western Ghats, India. Botanical Journal of the Linnean Society. 157:155-163. doi:10.1111/j.1095-8339.2008.00786.x.
- Kurinji crown - The Palni Hills are once again witnessing the mass flowering of neelakurinji.; TEXT & PHOTOGRAPHS by IAN LOCKWOOD; Volume 23 - Issue 17 :: Aug. 26-Sep. 08, 2006; Frontline Magazine; INDIA'S NATIONAL MAGAZINE from the publishers of THE HINDU
- Kurinji rules the hills - The latest instance in the 12-yearly flowering cycle is a big draw; by K.P.M. Basheer; Sep 13, 2006; The Hindu, Online edition of India's National Newspaper
- A Revision of the Strobilanthes kunthianus-Group (Phlebophyllum sensu Bremekamp) (Acanthaceae). Mark A. Carine, Jake M. Alexander and Robert W. Scotland. Kew Bulletin Vol. 59, No. 1 (2004), pp. 1–25