Hibiscus drop leaves anytime they are under stress. The spraying may have caused it. Don't worry, they'll snap out of it.

BTW, what did you spray them with? You should never spray hibiscus with Malathion or anything with oil in it.

Thanks bruggirl100. BUT, what I'm also concerned with is the fact that my leaves were yellow before I EVER sprayed. Also, any idea what the tiny white specks on my tree trunk might be? Do whiteflies only attack the leaves or the wood and stems also?

The leaves on my hibiscus are turning yellow, and as I have no experience of container plants in very hot weather,I was wondering if being in the direct sun in 32 degrees centigrade in the shade it too hot. Should I be giving it fertilizer every week. It was looking beautiful with lots of blooms, but this week the leaves are drooping slightly and are yellow. I have been watering it every evening, as the soil is always dry. It was a housewarming gift to me at the beginning of June, and has performed really well up till now. Any suggestions, please.