Written by: Mary Griggs, Colorado Master Gardener

If you crave a tropical look and feel in a cooler climate, try growing a hardy hibiscus plant full of huge, showy flowers. Native to North America, the oversized flowers feature tissue-thin, ruffled pink, red, magenta, and white petals with a central protruding stamen structure. Some varietals produce blooms with dark-colored centers.

In addition to adding color to your summer garden, hardy hibiscus blooms attract hummingbirds, dragonflies, and butterflies. While each bloom lasts only a day or two, it is quickly replaced by new blooms. You might be tempted to cut a bouquet, but don’t—hibiscus blooms are better suited to the landscape than being cut and placed in a vase since they usually wilt within a day.

What Is Hardy Hibiscus?

The term “hardy hibiscus” generally refers to cultivars of Hibiscus moscheutos that are bred to tolerate colder temperatures than most Hibiscus species, most of which are tropical species. These cold-hardy varieties are also known as “perennial hibiscus,” meaning they grow back every year. Most hardy hibiscus will reliably tolerate winter temperatures as far north as zone 5, but even zone 4 gardeners may be able to find varieties suitable for their growing conditions.

Some of the most common hardy hibiscus plants vary in size and bloom:

• Hibiscus moscheutos ‘Lady Baltimore’: This variety is 4 to 5 feet tall and up to 3 feet wide. It features light pink flowers with a red center.
• Hibiscus moscheutos ‘Summerific Perfect Storm’: This compact and well-branched variety produces dark purple foliage and can grow 3 feet tall and 4 feet wide. Its large 7-inch whitish-pink flowers have a red eye.
• Hibiscus moscheutos ‘Robert Fleming’: This compact variety is about 2 to 3 feet tall and wide at maturity. Its huge blooms are a deep, velvety red.

Hardy hibiscus is best planted in the spring after the threat of frost has passed. They bloom from mid-summer through the fall, with most profuse blooming in the summer.

Hardy hibiscus is best planted in a full-sun spot with well-drained soil enriched with compost. If grown in full sun in hot climates, consider providing shade for a respite from the beating sun. A hardy hibiscus grown in partial sun all day may produce fewer blooms than its full-sun counterpart. My hardy hibiscus plants are planted in native soil enriched with compost and are in full-sun all day.

Hibiscus plants should be spaced 2 to 3 feet apart; these plants can grow up to 72 inches tall and up to 3 feet wide. Sow seeds about 1/2 inch deep into well-draining soil. Maintain high humidity and warmth during germination.

If transplanting, keep the base of the stem in line with the soil line. To keep it in line, backfill soil into your planting hole to get the planting height right. The planting hole should be as deep as your planting container, two to three times wider than the current container. Once set in the hole, backfill with soil and firmly tamp and water in.

Hardy hibiscus rarely needs support or stakes since it grows sturdy, woody stems. However, if it gets limp or leggy due to insufficient light, it may need a grow-through support grid system to train the stems to remain upright.

Deadheading hardy hibiscus promotes more blooms, keeps the plant looking healthy, and discourages reseeding. Deadhead flowers once they start to fade and wilt. To deadhead, snap or pinch off the stem below the faded or withered flower, where it connects to main limb.

These plants do need plenty of nutrients and regular feeding.  You can use a slow-release fertilizer three times a year, including early spring, after the first blooming, and mid-summer.

If you can’t locate hardy hibiscus plants in a moist spot in your landscape, keep them adequately watered—but don’t overdo it. A hardy hibiscus is typically thirsty and needs a deep watering of at least 1 to 2 inches weekly. I water mine three times a week.  Since most of my plantings are drought tolerant varieties, I am ok with giving these plants extra water because they add so much to my landscape and give me a lot of joy.

Hardy hibiscus dies to the ground in winter, so cut it back to about 4 to 6 inches of growth in the fall or spring before new growth emerges. The root system will survive the winter, and new growth will emerge from the root system. Since these stems are woody, prune using loppers, a heavier cutting tool.

The best way to get a replica of the parent hardy hibiscus plant is to propagate it with stem cuttings.  Propagate with this method in the spring or early summer for best results. Good luck and happy gardening!

*Top Photo Credit: Nebraska Extension