Mention the unique phenomenon exhibited by Strobilanthes kunthiana (neelakurinji).

Hint: Nilgiri Hills, the Blue Mountains literally took their name from Neelakurinji's blue pure flowers. This species has a unique blooming cycle.

Complete answer:
Strobilanthes kunthiana, kurinji or neelakurinji is a shrub found in the Western Ghats shola forests of South India. Nilgiri Hills, the Blue Mountains literally took their name from Neelakurinji's blue pure flowers. At 1300 to 2400 metres above sea level Kurinji grows. It typically reaches a height of 30 to 60 cm. But under friendly conditions, they can grow well beyond 180 cm. The Kurinji plant was first described scientifically in the 19th century and belongs to the genus Strobilanthes. The genus includes approximately 250 species, 46 of them in India.

Only once in 12 years is Neelakurinji flourishing. In their blooming season Kurinji once covered the Anamalai Hills, Cardamom Hills, Nilgiri Hills, Palani Hills and Bababudangiri like a carpet. Plantations and dwellings now occupy a substantial part of their habitat. In Chandra Drona Hill Ranges, Neelakurinji flourished (Bababudan Giri), Karnataka District, Chikkamagaluru in 2006. All Bababudangiri hills had a blue, purple-flowered carpet. In addition to the Western Ghats, the Shevroys, the Anamalai hills of Idukki and Agali hills in Palakkad, in Kerala and in Karnataka Sanduru hills of Bellary district, are re-flower in 2018.

Note: The Kurinji plant was first described scientifically in the 19th century and belongs to the genus Strobilanthes. The average flowering activity of the majority of these species ranges from annual to 16-year blooming periods.