The first thing to check is the sunlight: it needs several hours of direct sun a day to produce buds. It also needs a coarse, fast draining, gritty compost. There are different theories about fertilizing--I have had the best luck with a 3-1-2 proportioned fertilizer, but if your water is very pure or acidic, you may need more phosphate. Anything more complicated, you might want to join GoY (it's free) and send Delonix1 a personal message.

I've found that giving plants that won't bloom a dose of epson salts helps. I had a minature orange tree for 5 years and didn't bloom. Gave it some epson salts and now it blooms very well.

Olelady/Barbara