Saffron ...

... well, not really. I grew these common crocus from corms which I planted in October. I thought I might have them ready for Christmas but no such luck. Lots of leaf - they grew and grew and outgrew the little bowl I'd used to plant them. Once I'd transplanted them they suddenly burst into flower. The crocus are starting to flower in the garden so maybe you can't force indoor ones to flower early the way you can with narcissus.