Thanks to my Facebook gardening buddies, I learn that the flower posted here is called Pentas. Armed with the name, I went googling and found more information in Autumn Belle's blog www.mynicegarden.com. Actually the specimen displayed here isn't mine but my SIL's. It is a perennial in the tropics and supposed to flower most of the time. There are a few other colours available too. Beautiful clusters of petals it has but without any fragrance.