How old is it? I had a young one that I planted last year, It did not flower that year, This year it has started to flower, I'm not sure how old it was when I bought it but I'm guessing it had been grown for a year already before the garden center sold it me. Some flowers don't flower for the first few years.They have to get used to their location and soil and establish before they start to flower. If yours is a young plant You have not had long then this is probably why It has not suddenly flowed yet.