I raised silk worms when I was in grade school. These worms are incredible eating machines. They are very picky eaters. On day, I ran out of mulberry leaves. In a panic, I fed the worms with hibiscus leaves. The leaves are shaped the same. The worms had no eyes anyway. They would not know the difference, I thought.
These worms were fussy little guys. They refused to eat. After some intense persuasion (I used a feather to brush the head of the worm, as any good silk worm tender was told to do), they reluctantly began to eat. They soon had the runs and were pretty sick for a while. It was not a pretty sight. These worms would have nothing to do with hibiscus.