Why is my hibiscus not blooming?

Hibiscus needs 6+ hours of direct sun — shade is the top cause of poor flowering. Other causes: too much nitrogen (promotes leaves, not flowers) — switch to a high-potassium feed; pot too large (hibiscus blooms better when slightly root-bound); recent hard pruning — allow 6–8 weeks recovery before expecting blooms. Phosphorus spray (12:61:0) applied to leaves triggers flowering within 2–3 weeks in healthy plants.