Hardy hibiscus is a stunning pollinator plant. Here's how to grow it

When you hear the word "hibiscus," you likely think of a tropical plant with short-lived flowers in several stunning colors sold throughout Greater Columbus each spring and summer as an annual flowering plant.

While the tropical hibiscus has no chance of surviving the cold temperatures of Ohio winters, hardy hibiscus is an herbaceous perennial which thrives in Ohio and boasts even more stunning flowers, albeit not in as many different colors as its tropical cousin.

Hardy hibiscus (Hibiscus moscheutos) is an herbaceous perennial in the mallow family and is sometimes called swamp rose mallow. Hardy hibiscus features delicate 8 to 10-inch flowers with ruffled petals in shades of red, pink, purple and white, and can grow to 4-6 feet tall with a shrub-like appearance. Hardy hibiscus is native to sections of the eastern U.S. and Canada, and tends to flourish in marshes, wetlands and along creek borders.

Hardy hibiscus is a wonderful pollinator plant, attracting bees, butterflies, hummingbirds and other pollinators.

Growing hardy hibiscus

To maximize the number of blooms on a hardy hibiscus, plant it in locations in the garden or landscape that receives a minimum of six hours of full sun. While this plant can thrive in partial shade, you can expect fewer blooms in such locations. Full-shade locations should be avoided for this plant.

Because hardy hibiscus are wetland plants in their native habitat, these are perfect plants for moist areas of the garden or landscape where other plants can be difficult to grow. If you don’t have an area of the garden or landscape with moist soils, be sure to provide supplemental irrigation, especially during periods of hot, dry weather.  

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Hardy hibiscus may need to be watered almost daily during periods of high temperatures when rainfall is infrequent, as the plant requires up to 2 inches of water per week. A 2-to-3-inch layer of organic mulch can help maintain soil moisture.

Hardy hibiscus does better in soils with adequate organic matter, so if your soil is low in organic matter, consider amending the soil with compost or peat moss before planting. Regular fertilization with a water-soluble fertilizer will stimulate bud development and flower bloom.

There are very few insects and disease organisms that attack hardy hibiscus, although Japanese beetles and other leaf-feeding insects sometimes chew holes in the leaves. Such feeding is rarely harmful to the overall health of the plant.

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Late bloomer

Hardy hibiscus blooms from mid-summer through early fall depending upon the variety. While its dainty blooms last only a day, they are followed with new blooms each day, so you can expect several weeks of stunning color. In the spring, hardy hibiscus is one of the last herbaceous perennials to green up, as it requires soil temperatures of 60 to 75 degrees Fahrenheit to break dormancy. When I first planted hardy hibiscus in my garden, I mistakenly thought that it did not survive the winter because it was late May before it greened up.

Popular hibiscus varieties

• Lord Baltimore: a hybrid variety with dark pink flowers with red centers. The blooms can grow up to 10 inches in diameter and the plants reach 5 feet tall and 3 feet wide.
• Luna Pink Swirl: produces stunning flowers with light pink and white swirled petals and red centers. The flowers can reach up to 8 inches wide and bloom from summer through early fall.
• Fireball: Known for its deep red flowers, this variety can tolerate both cold and heat.
• Robert Fleming: This compact variety is about 3 feet tall and wide at maturity, and its huge blooms are a deep, velvety red.
• Summerific Perfect Storm: This compact variety grows to 3 feet tall and 4 feet wide and has dark purple foliage. Its large pink flowers have a red center.

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Winter care

Since hardy hibiscus is cold-tolerant, it does not require much specialized winter care. While the foliage and stems of the plant will die back each winter, hardy hibiscus can be slow to die back in fall, so it may be best to wait until spring to remove the spent stem. Cutting the stem back before it is completely dormant could make the plant more susceptible to winter injury.

As with many perennial plants, mulching hardy hibiscus with straw, shredded hardwood mulch or wood chips can protect the roots from drying winter wind and sub-zero temperatures similar to the temperatures that occurred in Greater Columbus last December.

Mike Hogan is an Extension educator, Agriculture and Natural Resources, with Ohio State University Extension.hogan.1@osu.edu