I've got a hibiscus that's about 4 feet tall that I just started caring for. The leaves are curled down but I see no tiny insects on the leaves. I noticed that the root ball was about 1 inch below the top of the soil. I just removed the soil and am hoping that this helps. Do curled leaves sound like a symptom of the root ball planted too deep?
Curled Leaves on a Hibiscus
Many things can cause hibiscus wilting. Recent transplanting, over-watering, under-watering and wilt disease are potential culprits. I don't see much perlite in your potting mix which makes me wonder if your potting mix drains well enough. Soil should be damp, not wet. Fungal disease sets in if roots or trunk stay wet. Water when the soil is dry 1 inch down. Is there a drainage hole in the bottom of your pot?