Some varietals produce blooms with dark-colored centers.
Hardy hibiscus can be planted in spring when there is no risk of frost.
The plants will grow quickly, some emerging each summer with blooms the size of dinner plates.
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While each bloom lasts only a day or two, it is quickly replaced by new blooms.
What Is Hardy Hibiscus?
These cold-hardy varieties are also known as “perennial hibiscus,” meaning they grow back every year.
The Spruce / Letícia Almeida
Otherwise, you might start growing hibiscus seeds indoors 12 weeks before the expected last frost date.
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.
The Spruce / Letícia Almeida
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.
The Spruce / Letícia Almeida
To keep it in line, backfill soil into your planting hole to get the planting height right.
Once set in the hole, backfill with fresh soil.
Hardy hibiscus rarely needs support or stakes since it grows sturdy, woody stems.
The Spruce / Letícia Almeida
They also grow well when planted aroundwater featuresand ponds.
A hardy hibiscus is typically thirsty and needs a deep watering of at least 1 to 2 inches weekly.
It needs to be watered almost every day.
Small plants with fewer leaves need less water than large, leafy ones.
A good indicator that your plant needs watering is when an inch down into the soil is dry.
Hibiscus plants flower best in temperatures between 65 and 75 degrees Fahrenheit.
As the water evaporates, the humidity will rise around the plant.
A small space humidifier will also raisehumidity levelsin your home.
Fertilizer
Hardy hibiscus plants need plenty of nutrients and regular feeding.
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.
Buy seeds or collect them from the pods that form after the plant has flowered.
If the flowers were pollinated, the plant would produce pods.
Each pod contains between 10 and 20 seeds.
The seeds need to be stratified and scarified for the best results.
Keep them dry in a protected container outdoors so they can feel normal winter temperatures (stratification).
Begin to sow them indoors about six to 12 weeks before the last frost.
Or you could sow them directly in the ground after the last frost.
Ensure the pot has ample drainage holes.
Repot container-grown hibiscus into a larger pot every two to three years.
If you live with mild temperatures year-round, your hardy hibiscus will also thrive outdoors throughout the year.
But if you live where winter temperatures dip below freezing, you must protect your hardy hibiscus plants.
Wrap it in heavy cloth (burlap) or tarp.
The material must be able to withstand freezing and frosty conditions.
These insects includeaphids,Japanese beetles,mealybugs,sawfly larvae,spider mites,thrips, andwhiteflies.
Hardy Hibiscus Flowers Appearance and Fragrance
Unlike tropical hibiscus, hardy varieties have no discernible fragrance.
The flowers look like the tropical variety, with five papery petals and a central protruding stamen.
They come in white, pink, and red.
Some types have a dark “eye” at the bloom’s center.
The blooms can vary in size from 6 to 12 inches wide.
How to Encourage More Blooms
Failure to bloom is very often the result of shady conditions.
Hardy hibiscus may refuse to flower unless fed aggressively.
Weekly feeding with a diluted liquid fertilizer may prompt your plant to produce plentiful flowers.
Deadhead flowers once they start to fade and wilt.
Unseasonal yellowing can be a sign of too much water or not enough fertilizer.
Temperatures between 65 to 75 F are needed for proper bud development.
If the leaves perk up, slowly inch the plant to full sun over time.
Add fertilizer to the watering regimen.
Hibiscus plants are generally long-lived.
Hardy hibiscus can live up to 20 years or so.
The two types of hibiscus are hardy andtropical.
The plant can be grown in partial shade but won’t bloom well.
It needs sun to create blooms.
Even one or two hours a day can help increase the blooms.
Many tropical hibiscus plants can grow indoors as houseplants, but it’s best to leave hardy hibiscus outdoors.
Pests in Gardens and Landscapes.
University of California Agriculture Natural Resources.
Hibiscus Diseases resulting from Fungi.The Connecticut Agricultural Experiment Station.
