Hibiscus adds a tropical vibe to any landscape, whether planted in patio pots or in a relaxing warm-climate garden. Though some varieties thrive in the ground in summery climates, others do well in pots that can be brought indoors as temperatures cool off after summer. In each case, pruning is best done when temperatures are on the increase, rather than before autumn or winter.
The Benefits of Pruning
A light pruning on parts of the hibiscus encourages the plant to create more branches, which results in a fuller specimen. More branches equals more places for flowers to bloom, resulting in a lush, healthy-looking hibiscus. Pruning hibiscus to remove dead or ailing branches also helps the plant stay healthy. It's also the best way to encourage the overall shape of the hibiscus.
When and How to Deadhead
Deadheading—the process of removing faded, wilting blooms—benefits many types of flowers, including hibiscus, since it helps the plant redirect its energy into creating more blooms. Inspect the plant every couple days for flowers that are done blooming. The goal is to deadhead before seed pods emerge, as this is another stage of the flower's lifespan. Grab the stem of the individual wilted flower and snap it off where it joins the plant, causing no harm to this larger branch or stem. If you prefer to use tools, bypass hand pruners are ideal, speeding up the process when deadheading lots of flowers.
- Note: When either pruning or deadheading hibiscus with tools, make sure the blades are sharp and clean. Dull blades can tear stalks, and dirty blades can also spread plant diseases. To clean the blades of pruners, wipe them down with rubbing alcohol or an alcohol-based hand sanitizer before each use, or after cutting a visibly diseased plant stem.
Tropical and Perennial Differences
A hibiscus may be a tender tropical plant or a hardy perennial plant, depending upon the variety. Tropical hibiscus varieties don't tolerate cold well, so they aren't good options for a garden outside of USDA plant hardiness zones 10 to 12. Even so, a tropical hibiscus can be kept outdoors in a pot in colder climates, then brought indoors when cold-weather seasons approach. The perennial hibiscus varieties tolerate winters and die back to the ground every year, much like many other perennial plants in a cool-climate garden. The leaves on a perennial hibiscus tend to be lighter in color than on their tropical relatives. Surprisingly, the flowers on a hardy perennial variety are also generally larger than with tropical hibiscus.
When to Prune Hibiscus
Perennial hibiscus: Major end-of-growing-season pruning isn't recommended for perennial hibiscus, as this can severely affect the plant's growth the following spring, even causing branches to die. Instead, wait until late winter or early spring when temperatures start to rise. This can even be done as new growth starts to form, but make sure to cut only the old growth. Trim virtually the entire plant (other than brand-new growth) down to about six inches above the ground, keeping the stems approximately the same length. This type of maintenance is also known as hard pruning.
Pruning a perennial hibiscus after the first bloom can also encourage more blooms later in the summer. Prune less than 1/3 of the plant back so the hibiscus stays healthy. Feel free to do minor pruning during spring or summer to help shape the plant as well.
Tropical hibiscus: The tropical varieties can be pruned any time during the growing season to help shape them and to remove dead branches. A tropical hibiscus can also be cut back at the end of fall, once the growing season nears its end and the plant goes into dormancy. As with perennial varieties, never remove more than 1/3 of the plant at a time.
When dealing with potted hibiscus brought indoors to overwinter, when to prune it depends upon where you keep the plant inside. If you place it in a cool, dark place such as a basement, save the pruning until late winter or early spring. If you keep it in a sunny and warm greenhouse-style environment. feel free to prune stems in fall once you bring the pot indoors.
Pruning to Guide the Shape
Hibiscus plants tend to get tall and lanky, sometimes so much that the plant becomes top-heavy with stalks leaning in different directions, making the hibiscus look sparse in the middle. Selective pruning is the key to filling in sparse areas in a bush-style hibiscus, as well as helping a plant that's too tall and thin to branch outwards. Identifying the leaf nodes is the key to guiding new growth as you prune the plant.
- Inspect the plant to determine if it needs more inward-facing growth, or more new growth facing outwards.
- Pick a branch to prune, looking for a leaf node about 1/3 the way down from the tip. Nodes are the bumps on the stems from which leaves grow. An eligible node for pruning may have a leaf on it, or it may just look and feel like a bump.
- To encourage the plant to grow inwards, prune 1/4-inch above a node facing the center of the plant. New growth will sprout from the node and grow inward.
- To encourage new growth aiming outwards, prune 1/4-inch above a node that faces the outside of the shrub.
- Repeat the process on a number of branches, but no more than 1/3 of the plant at a time. Use bypass hand pruners to make the cuts.
Help for Old, Unhealthy Plants
A mature tropical hibiscus with lots of dead branches may benefit from a hard prune, or cutting back much, if not all, of the old growth. This is also helpful for a plant that hasn't bloomed as much as it used to, or one with scrawny and sparse new growth. Cut the branches down to a foot or so from the ground, leaving at least several leaf nodes intact, as these nodes are where new growth occurs. It may take some time for the hibiscus to recover, but new stems will eventually create new leaves, buds and blooms event. Expect to wait at least a couple months for the first new flowers after a hard prune.