Probably just ther wrong time of year, Carohit. Camomile flowers in the summer, even in places where it is summer all year round. They also like cool growing conditions so your plants would probably prefer to be on the shady side of your house.

The temperature here is around 15- 22 degree C ..not sure if it is the right temperature for cammomile.

Carohit, Annual (or German) Chamomile (Matricaria recutita) normally grows green through the winter, here in the Arizona low desert, but doesn't flower until around late February to March. Perennial (or Roman) Chamomile (Chamemelum nobile) will take at least until June to bloom, and may wait until 2014, when started from seeds. If your summer temps are like ours (43º C plus) Perennial Chamomile will be happiest in the summer where it gets afternoon shade. Annual Chamomile, of course, isn't expected to live through the summer here, even though it is the best tasting species.

Thank you very much for your help tugbrethil and bulbholic for a detailed answer

You're welcome!