Q.How Do I Get My Hibiscus Bush to Get Its Fuller Bushier Leaves Back?
I have my hibiscus in a large ceramic pot with a good size hole for drainage and also about 2 inches of rocks. It’s about 4 yrs old and the leaves are really scrawny and it’s not very bushy at all, even in the summer. How can I get my hibiscus to get its bigger, bushier leaves?

Certified GKH Gardening Expert
Pruning should help and spring is the ideal time for it. This article will explain how to prune your hibiscus: https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/tips-for-pruning-hibiscus-plants-when-to-prune-hibiscus.htm
Also, be sure that it's receiving adequate light, as too little light will result in a leggy, spindly looking plant rather than a nice full one.