Hibiscus can be herbaceous perennials or woody shrubs, depending on the species. H. lasiocarpos, also known as rose mallow, is hardy in U.S. Department of Agriculture hardiness zones 5 to 9 while H. coccineus or scarlet rose mallow is hardy in zones 6 to 9. H. rosa-sinensis or Chinese hibiscus is hardy in zones 9 to 11 while H. syriacus or rose of Sharon is hardy in zones 5 to 8. Regardless of the species, there are four methods commonly used to propagate hibiscus.
Select a stem that is at least 3 feet tall. Prune off all of the leaves and branches from a 6- to 8-inch section of stem approximately 1 foot from the tip of the stem. Scrape off a 1/2- to 1-inch wide ring of bark at the center of the stripped area of stem. Wrap dampened sphagnum moss around the stem where the bark has been scraped off and secure with twine. Cover the sphagnum moss with a strip of plastic sheeting and wrap aluminum foil over the plastic to hold in the moisture and deflect heat. The roots will emerge around the plastic after one to 12 months, at which time the foil and plastic should be removed and the stem cut just below the roots. Pot the new hibiscus in fast-draining potting soil.
Take 3- to 5-inch-long softwood cuttings in the spring or early summer, 3- to 6-inch long semi-hardwood cuttings between late spring and late summer or 4- to 30-inch long hardwood cuttings between late fall and early spring. Pour peat-based potting soil into a 6- to 8-inch diameter container and moisten it with room-temperature water. Remove the leaves from the lower 2 inches of stem and dip the tip of the stem in rooting hormone. Insert the cutting 1 inch deep into the soil. Remove the bottle cap and bottom of a 2-liter pop bottle and place it over the cuttings. Keep the container in a warm, brightly lit location out of direct sunlight and keep the soil uniformly moist. The cuttings should develop a strong root system after a few months at which time they can be potted up separately.
Herbaceous perennial hibiscus can be propagated by dividing clumps in early spring. Lift the clump out of the soil with a shovel. Use your fingers to work apart the large clump into separate smaller clumps, each with a healthy root mass to support the stems. Re-plant the new hibiscus plants immediately. They can be potted or planted in a different location. Water them generously right after planting and keep the soil uniformly moist until they become well-established.
Plant hibiscus seeds indoors three months before the last expected frost or outdoors after the last frost. The seeds may also be planted directly in the garden in the fall. Leave the flowers on the plant to form seed capsules. Remove the seeds from the capsules after they become dry and split open. Place them in a paper bag and keep them in the refrigerator for spring planting. Remove the seeds from the refrigerator and soak them in warm water for one hour just before planting them. Sow them in peat pots or small containers with pre-moistened peat-based potting soil. The seeds should be planted 1 inch apart and no deeper than twice their diameter. Place a plastic bag or cover over the container to keep the soil moist. Keep them in a brightly lit area but not in direct sunlight. Remove the covering when the seedlings are 1 to 2 inches high. Pot them separately when they begin to grow adult leaves.
- Missouri Botanical Society: Hibiscus lasiocarpos
- Missouri Botanical Society: Hibiscus coccineus
- Missouri Botanical Society: Hibiscus rosa-sinensis
- Missouri Botanical Society: Hibiscus syriacus
- Clemson University Cooperative Extension: Hibiscus
- North Dakota State University: Propagation of Hibiscus
- Royal Horticultural Society: Trees and Shrubs from Seed
- University of Florida IFAS Extension: EDIS: Propagation of Landscape Plants
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