While Rajamala at Munnar in the Western Ghats awaits another blossoming of ‘Neelakurinji’ ( Strobilanthes kunthiana ) in 2018, the hills of Parunthumpara and Kalyanathandu are in splendour with the purple-blue colour of Neelakurinji.
Neelakurinji blooms once in 12 years, but there are many sub-species whose flowering period range from a year to 16 years. Of the 200 species of Strobilanthes found in Asia, Munnar alone hosts 45 species and the last blossoming was reported in September 2014.
The Strobilanthes kunthiana last bloomed at Rajamala in 2006.
Strobilanthes kunthiana blossoms on hills at 1,300 to 2,400 metres above mean sea level (MSL), the sub-species flower at an altitude below that level. It is believed that the Neelakurnji that have now come into flower are a sub-species of Strobialnthes found at 600 to 900 metres above MSL. This sub-species had blossomed at Thekkady, Wagamon and Pampanar grasslands. Now it has flowered in acres of land at Kalyanathandu, near Vazhavara, on the Thodupuzha-Puliyanmala State highway and at Parunthumpara.
Biologists say topographical and climatic factors could effect changes in the blossoming period. Neelakurinji has three phases of growth — blossoming, seeding and decaying. The blossoming period extends to two months and the sunlight makes it all blue covered mountains at a distant view.