evidence: While some plants have been known to live for as long as a century before blooming, a social media post claims one spectacular Himalayan flower takes rarity to a new extreme – blossoming only once in 400 years. [...] It is not the first time a photo of the same plant has been circulated on social media accompanied by the 400-year claim. In November, 2019, an Instagram user claimed an image of Rheum nobile was a "Mahameru flower that blooms once every 400 years in the Himalayas", adding that those fortunate enough to see the plant in bloom would receive a "lifetime of good luck". [...] A viral photo shared on social media does not show a Himalayan plant that blooms every 400 years, as claimed. Rather, it shows a plant, Rheum nobile, that flowers once in its lifetime before dying. Researchers say this occurs after around 33 years, on average.