Can I cut my hibiscus all the way back?
When pruning hibiscus plants, they should be cut about a third of the way back, leaving at least two to three nodes on the branches for new growth to emerge. These cuts should be made just above the nodes, leaving about a quarter-inch (0.5 cm.).
Up until Frost ideally you want to deadhead as soon as the last flower on the stem is done flowering
Once the plant starts to flower, remove spent blooms as they finish flowering. This plant is known for its incredible flowers, and looks much more attractive when the wilted blooms are removed. In the late fall, long after flowering is finished, you will need to prune hardy hibiscus stems following a hard frost.
With a Perennial Hibiscus, keep the flowers deadheaded and trim out damaged leaves and branches and old-growth lightly throughout their active growing season. Cut back one-third or less of the plants' new growth overall to encourage more branching and more blooming.
Hibiscus yellow leaves are common and usually not anything to worry about. Often, hibiscus leaves turning yellow will correct itself. In some cases, pruning of the entire plant is necessary.
Although deadheading isn't a necessary aspect of any tropical hibiscus plant care, removing faded flowers will help maintain the plant's beauty, improve its appearance, develop more blooms, and divert the plant's energy into creating more blooms.
How to Deadhead a Plant. Deadheading flowers is very simple. As plants fade out of bloom, pinch or cut off the flower stem below the spent flower and just above the first set of full, healthy leaves. Repeat with all the dead flowers on the plant.
The hibiscus flower only lasts a day, although many new hybrids have been bred which now last longer, even up to three days. Try not to think of this as a bad thing, many plants bloom only once a year for two or three weeks and then you have to wait a whole year for a repeat performance.
Cut Back Stringy and Leggy Limbs
Hibiscus plants tolerate and even benefit from a heavy pruning, and this is the only way to bring a leggy bush back under control. Cut back or remove all of the leggy limbs to bring the plant back into the desired shape. Also remove any dead or damaged wood at this time.
To prepare a hardy hibiscus for winter, apply a heavy layer of organic mulch to the soil around the plant to protect its roots. Place frost cloths or string lights over the plant to provide warmth and keep the leaves from freezing.
How do I know if my hibiscus is perennial or annual?
If your hibiscus has dull medium green heart shaped leaves, dinner plate sized white, pink or red flowers with HUGE, bomb shaped buds (2-4" in length!), it is a perennial, hardy hibiscus.
Keeping Hibiscus Inside Over Winter
(That said, if you have a hardy hibiscus, which is sold in the perennials section of your local garden center, that plant can stay outdoors over winter. It will go dormant this fall, rest over winter, and produce new growth in late spring with flowers following in summer).