When to prune hibiscus usually depends on where you live. However, most hibiscus pruning occurs during spring. For the most part, hibiscus plants can be lightly pruned in late summer or early fall, but no hibiscus pruning should be done during late fall or winter.One of the downsides to waiting later in the season to prune is that plants may not develop as many branches, and they will put out fewer blooms.owever, most hibiscus pruning occurs during spring. For the most part, hibiscus plants can be lightly pruned in late summer or early fall, but no hibiscus pruning should be done during late fall or winter.