What a strange summer this was! My hibiscus was attacked by a never seen insect with the holes the only evidence. I tried a butterfly garden compatible 3 in 1 spray to no avail. It never jumped to the adjacent anemones or any other plant. She valiantly bloomed throughtout but now is a sad, holey stalk. Will it come back and what can I do next year?
It looks like your hibiscus has damage from hibiscus sawflies. Look carefully at the undersides of the leaves to see if you find any tiny, caterpillar-like insects. You may need a hand lens to see them. The following page on our website has information about sawflies and what you can do. https://extension.umd.edu/hgic/sawflies-flowers Leaves should come back next year, but sawflies are a common pest of hibiscus. Check the leaves periodically for signs of chewing. Apply horticultural oil according to the label instructions.