What is the name of the flower that only blooms once, after 15 years? - it has a peachy orangeish colour?

Answer 1

is it the cactus rose

Answer 2

You might be thinking of Rafflesia, a giant tropical orange flower which blooms only after many years (in cultivation, at least) and smells horrible. There are lots of other shy bloomers, though, which grow slowly and wait for the right conditions to bloom, like the Century Plant. That one actually may bloom in as little as 15 years, or 25, or more, and once they bloom, they die. But they leave small "pups" behind, plus whatever seeds they produced when they bloomed.