Mesua ferrea

Mesua ferrea, the Sri Lankan ironwood, Indian rose chestnut, or cobra's saffron, is a species in the family Calophyllaceae. This slow-growing tree is named after the heaviness and hardness of its timber. It is widely cultivated as an ornamental due to its graceful shape, grayish-green foliage with a beautiful pink to red flush of drooping young leaves, and large, fragrant white flowers. 
It is native to wet, tropical parts of Sri Lanka, South India.