Hardy Hibiscus is a show-stopper in the garden! Their sizeable, showy, vibrantly colored blossoms add a touch of the tropics to any landscape. Though a perennial in some climates, as their name implies, gardeners in colder climates may need to overwinter their hibiscus to enjoy their beauty year after year.
Fear not, fellow hibiscus enthusiasts! Overwintering your hardy hibiscus is quite simple. With a few basic steps you can ensure your hibiscus will come back strong and blooming next spring, and the spring after that, and …!
Hardy, in this context means that this hybrid has been bred to tolerate colder temperatures, even some frost and freezing temperatures. Hardy Hibiscus can be grown successfully as far north as USDA Zones 4 and 5, though to ensure that your hibiscus survives the winter, we recommend taking the following steps.
Protecting Your Hibiscus
- Water deeply in the fall. Before the first extended freeze, give your hibiscus a good soak. This will help the plant store moisture in its roots and will be vital for its survival during the dry winter months.
- Wait for a killing frost. This will signal to the plant that it's time to hunker down for the winter. The leaves will turn brown and die back naturally. Resist the urge to cut them back early, as they do provide some insulating protection for the plant.
- Trim the stems. Once the leaves have died back, cut the stems to about 6 to 8 inches above the ground. This will help your plant survive those cold winter winds and will make it easier to apply mulch.
- Apply a thick layer of mulch. This is the most important step to successfully overwinter your hibiscus. Your hibiscus plant will reap the most benefit with a layer of mulch 8-12 inches deep around the base of the plant. Chopped leaves, straw, or pine needles are all good options. The mulch will insulate the roots and help prevent the soil from freezing. If using a lighter mulch, like leaves, you may have to reapply if the winter winds blow your mulch away.
- Provide additional protection In extremely cold climates. This may include wrapping the plant in burlap, using a plant protection bag, or building a temporary shelter around it.
Be patient! Hardy hibiscus are slow starters in the spring. The soil temperature needs to reach about 70° F (21° C) to bring them out of their winter slumber. As the temperatures and longer days herald the beginning of spring, remove the mulch from around the plant. This will allow the sun to warm the soil more quickly.
Once you see new sprouts emerge, give them a dose of fertilizer. Use a balanced fertilizer with an NPK of 10-10-10 or 20-20-20. If using a water-soluble fertilizer, use at half strength to avoid burning the roots. Feed your Hardy Hibiscus every 2 to 3 weeks in the spring and summer while actively blooming. Once blooming has stopped, you can fertilize every 4 to 5 weeks in the fall. Tidy up your hibiscus by removing any old stems and leaves.
With very little effort, taking the steps above will ensure that your hardy hibiscus will bounce back healthy and strong in the spring. Your reward will be the splendor of those flamboyant, impressive blossoms all summer long.