Tulsi is one of the most sacred plants in Hindu religion. There are two varieties of Tulsi that are venerated - Rama Tulsi and Krishna / Shyama Tulsi (the dark- coloured)
There is a Tulsi-maadam (an altar bearing the Tulsi plant) in most Hindu households. The plant is believed to sanctify and guide to heaven, all those who grow and worship it. Tulsi is extensively used to maintain ritual purity, i.e. to purify things if polluted and also to ward away evil.
Most Hindus revere the Tulsi leaf because it is believed to please Lord Vishnu. Tulsi is regarded as a Goddess and also a consort of Lord Vishnu in most parts of the country. Tulsi is ceremonially married to Lord Vishnu on the eleventh day of the month of Karthik every year. This ritual is called ‘Tulsi vivaha’ and it marks the beginning of the auspicious marriage season in India.