Answer: Two things affect blooming - immaturity and incorrect cultural practices. It sounds as though you're taking good care of your champaca, so I'd chalk the problem up to lack of maturity. Champaca trees can be slow to establish, which will retard flowering. I suspect your tree will begin to flower for you within the next 12 months. Next spring, you may want to try a bloom-booster fertilizer with high Phosphate, something like 10-50-10. They sell it in Home Depot for roses, azaleas (doesn't matter). Water soluable is the best action, and I recommend to spray leaves (absorbs faster and better than through roots). Another (new) fertilizer for blooming that I bought from Home Depot - granulated "Colorburst Flowering Plant Food 15-30-15".
Best wishes with your garden!
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