Hibiscus Freeze Protection

Hardy Hibiscus

• Hardy hibiscuses (Hibiscus moscheutos) are perennial plants with large, disk-shaped flowers. These plants are cold hardy to U.S. Department of Agriculture zone 4 and only need minimal protection for their roots in the winter. Once your hardy hibiscus has died back, remove all the dead stems and cover the roots with 12 inches of leaves or pine straw. Building a circle of chicken wire around the roots and filling it keeps the mulch from blowing away. Confederate rose (Hibiscus mutabilis) is a hardy hibiscus that dies back in USDA zones 7 and 8 and is a deciduous shrub in zones 9 and above. In colder zones, cut the plant stalks back to 6 inches, construct a circle of chicken wire around the plant and pack it with pine straw or leaves 12 inches thick. In USDA zones 9 and up, mulch is all that is needed unless there is a cold snap, but even then, the plant will probably not die completely back.

Perennial Hibiscus

• Perennial hibiscus or rose of Sharon (Hibiscus syriacus) is a large, deciduous shrub that is hardy to USDA zones 5 through 8. Rose of Sharon will lose its leaves in the fall and usually survives the winter cold without much protection other than a 6-inch layer of mulch. During extreme cold snaps, covering the plant with blankets may prevent splitting from frozen wood.

Tropical Hibiscus

• Tropical hibiscuses are only hardy to USDA zone 9 and can be damaged by temperatures below 40 degrees Fahrenheit. Bring container plants inside during cold weather. For occasional cold snaps in zones 9 and up, water in-ground plants well and cover with blankets. This may prevent limb damage, but leaves will drop anytime they are exposed to cold temperatures. If the roots do not freeze, the plant will recover when temperatures warm.

Annual Hibiscus

• Hibiscuses that are easily grown from seed, such as H. acetosella, H. sabdariffa and H. abelmoschus, are considered annual plants and do not need to be protected from cold. In USDA zones 10 and above, these plants may come back from the base but are usually replanted from seeds in the spring. If you want to try to save the roots and base of the plant, place 6 inches of mulch around them before a freeze.