Hardy hibiscus is a collection of huge, tropical-like bloom colors produced by several hibiscus perennial shrubs. Hardy hibiscus has a lot of the biggest blooms of any perennial garden bushes. The Dinner Plate hibiscus (Hibiscus moscheutos), for example, is a cold-hardy shrub with huge, flat circular blooms up to 9″ (22 cm) wide.
Hibiscus flowers are commonly associated with tropical blooms that flourish in warm climates. Hardy hibiscus, on the other hand, grows in USDA zones 4 through 9. Hardy hibiscus plants will flourish and bloom in your front or backyard even if you get below-freezing temperatures throughout the winter months.
Cold-hardy hibiscus may create beautiful blossoms from mid-summer to late autumn in the mild, humid climates of Florida and northern states. This is a comprehensive guide to perennial hibiscus plant growth for cold weather climates. In addition, you’ll learn about hardy hibiscus cultivars and hybrids that can endure temperatures as low as -30°F (-34°C).
What is Hardy Hibiscus
Hardy Hibiscus is a genus of perennial flowering shrubs or tiny trees in the Malvaceae family. Rose of Sharon (Hibiscus syriacus) is one of them. Rose of Sharon (Hibiscus syriacus), rose mallow (Hibiscus coccineus), and Hibiscus moscheutos, sometimes known as rose mallow or swamp hibiscus, are the three major hardy hibiscus species. The lovely flowers range in size from 2″ to 9″ (5 – 22 cm) and are available year-round.
Hardy hibiscus thrives in USDA zones 5 to 9 and thrives in freezing conditions. Hardy hibiscus plants can be grown outside in zone 4 with the help of mulching the root zone in certain parts of the country. Hibiscus plants are typically large bushes or tiny blooming trees that bloom every year.
Rose of Sharon grows between 8 and 12 feet (2.4 and 3.6 meters) tall and 10 feet (3 meters) broad, making it the largest of the hardy hibiscus species. Rose mallow bushes are 3 to 7 feet (1 to 2.1 meters) tall and 4 feet (1.2 meters) broad.
Hardy hibiscus has lovely leaves in addition to its stunning big “dinner plate” blooms. Certain types have heart-shaped ovate leaves, while others have lobed, palmate leaves. The leaves are lush and green. Hardy hibiscus varieties differ from tropical hibiscus in that they flourish in chilly environments.
Only USDA zones 10 through 12 are suitable for tropical hibiscus species like Chinese hibiscus (Hibiscus rosa-sinensis). Additionally, hibiscus plants grown in the tropics tend to produce larger, more spectacular blooms.
How to Care for Hardy Hibiscus
Grow the shrub or hibiscus tree in well-draining ground that holds moisture to care for hardy hibiscus. During hot weather, water hardy hibiscus plants are frequently watered. In the spring, feed hibiscus with high potassium feed and trim branches so that new development appears. In the autumn, you can expect to see deadhead hardy hibiscus.
Hardy Hibiscus Flowers
Hardy hibiscus flowers come in white, pink, purple, and red colors and may be up to three feet across. From the center of the funnel-shaped hibiscus blossoms, a wide plate-like disc with an protruding stamen emerges. Purple, red, pink, and white are the colors of the saucer-sized flowers.
A contrasting, dark-colored center appears in some Hibiscus perennial blooms. Hibiscus Hardy Perennial starts flowering in the middle of summer. Just one to three days after opening, the individual blooms close. The giant flowering shrub, on the other hand, will continue to bloom until fall.
Varieties of Hardy Hibiscus
Rose of Sharon (Hibiscus syriacus) flowers come in a variety of cultivars and hybrids. The hardy hibiscus Rose of Sharon (Hibiscus syriacus) is the largest. Because of its gigantic saucer blooms, Hibiscus moscheutos is a smaller shrub known as “Dinner Plate” hibiscus. Rose mallow (Hibiscus coccineus) is a 6-foot (1.8-meter) tall perennial shrub.
Hardy hibiscus bushes may be huge, spreading bushy plants or small shrubs for tiny gardens, depending on the variety. For growing in cold climates, here are a few of the most stunning cold-hardy hibiscus plants:
- Hibiscus moscheutos ‘Luna White’—8″ (20 cm) across, magnificent, brilliant white saucer flowers with crimson centers. A compact perennial shrub. Hibiscus low-growing hardy grows to be 2–3 feet (0.6–1 m) tall.
- Hibiscus coccineus ‘Berry Awesome’—This deciduous shrub has massive pink disc-like flowers that bloom continuously from mid to late summer, and it is also known as “dinner plate hibiscus.” It is 5 feet (1.5 meters) broad and 4 feet (1.2 meters) tall with a pink coloration.
- Hibiscus moscheutos ‘Fireball Hibiscus’—The crimson blooms of this robust hibiscus can grow up to 10 inches (25 cm) broad and bloom until late in the season. Hibiscus plants 4 to 6 feet tall known as the hardy ‘Fireball. It is three feet (one metre) broad and tall.
- Hibiscus coccineus ‘Midnight Marvel’—With dark palmate leaves and massive 9-inch (22-cm) crimson blooms, this magnificent hardy hibiscus plant is a showstopper. The blooms last one day, but the shrub blooms from mid-summer until fall. The spiky hibiscus mallow grows to be 4 feet (1.2 meters) tall.
- Hibiscus syriacus ‘Pink Chiffon’—Beautiful ruffled semi-double, light pink blooms 3″ (8 cm) across make up a bushy hibiscus perennial. The hardy shrub develops to be between 8 and 12 feet (2.4 and 3.6 cm) tall.
Hardy Hibiscus Care
To enhance beauty and foliage to your front or back yard, we’ll explore how to grow hardy hibiscus perennial shrubs in greater depth.
Where to Plant Hardy Hibiscus Shrubs
You should place Hardy hibiscus in the brightest area of your garden since it requires around six hours of sunlight everyday. In partial shade, Rose of Sharon and rosemallow plants may be grown. If you plant hardy hibiscus in shaded regions of your yard, however, they will not produce as much blossoms.
To take care of hardy hibiscus bushes and trees, it’s important to keep the plant from getting too much or too little light. On hot summer days, intense, direct sunlight can cause leaves to yellow. When growing hardy hibiscus in scorching tropical climates, this is often the case. You may run into trouble with Powdery Mildew if a small hardy Hibiscus tree or shrub is in continuous shade.
The Best Soil for Growing Hardy Hibiscus
Moist soil with excellent drainage is ideal for Hardy hibiscus. Loose, airy soil with compost or peat moss as an organic substance is the ideal sort. If the soil is too clayey or dry and sandy, Hibiscus soil needs to be amended. Because they grow in wet soil with medium drainage, certain hardy hibiscus shrubs are also known as swamp hibiscus.
In most cases, ensuring the ground is constantly moist in the summer is the best way to take care of rose of Sharon, rose mallows, and swamp hibiscus. By doing this, you’ll encourage prolific blooming and ensure that you have a steady supply of large dinner-plate flowers throughout the summer.
Watering Hardy Hibiscus Plants
Every week in the summer and twice a week in hot weather, water-hardy hibiscus bushes are trimmed. You should water sufficiently so that the land is evenly wet when caring for hibiscus. In the winter, you should refrain from watering unless the soil is completely dry. When watering hardy hibiscus plants, here are a few helpful guidelines:
- To avoid root rot, don’t overwater drought-tolerant plants.
- Make sure the earth around the hibiscus roots is not waterlogged.
- To avoid powdery mildew, always water the ground and avoid dampening the leaves.
How to Grow Hibiscus in Pots
If you have a big enough container, Hardy Hibiscus plants may grow in it. In a loose potting soil combination of one-part peat moss and one-part perlite, grow the dwarf hibiscus shrub. To keep the soil slightly moist, water the potting mix frequently. In the brightest location on your patio, balcony, or deck, place the potted hibiscus plants. To protect the hibiscus plant from strong direct sunlight when growing it indoors, cover it with a pot.
How to Prune Hardy Hibiscus Bushes
Remove old growth or cut the shrub back in winter only to prune hardy hibiscus bushes. Every year, Hardy hibiscus plants lose their leaves, and in the spring, new foliage emerges from the ground. In early summer, you can also trim branch tips to encourage branching and abundant blooming.
How to Fertilize Hardy Hibiscus
Potassium-rich fertilizer, along with sufficient nitrogen, boosts growth and blooming in Hardy hibiscus trees and shrubs. In most cases, a layer of organically rich compost in the spring is sufficient to support fast development. Another option is to use a slow-release organic fertilizer on the hardy hibiscus.
Make sure you don’t fertilizer the plant excessively if you decide to use a commercial fertilizer. To ensure the nutrient profile is optimal, choose a fertilizer with an NPK rating of 10-4-12 or 9-3-13. Excessive phosphorus may hamper flowering as well as plant development.
Hardy hibiscus varieties are more likely to grow from seed than tropical hibiscus plants. Hibiscus stem cuttings and seed are the two simplest methods to develop new hibiscus plants from the mother plant. Now, let’s take a look at how to grow hardy hibiscus.
How to propagate hibiscus from seed
You may gather seeds for growing if your hibiscus bushes create seeds, but not all do. Using a sharp knife, make a little incision in the seeds. Before planting in a light soil mix, soak the seeds overnight. Keep the soil moist and put it in a warm area with plastic coverings. Seedlings emerge between two and four weeks.
How to propagate hibiscus from stem cuttings
Hibiscus can be propagated most easily by cutting off the stems. In the spring, cut a 6-inch (15 cm) healthy softwood hibiscus stem and remove the lower leaves. Put the end of the branch in a pot with a loose, moist potting soil and dip it in rooting hormone. To boost humidity, cover the pot with a plastic bag.
Then, keep it somewhere around 60°F (15°C) for a while. Keep the potting soil moist at all times. New leaves will take a couple of months to develop, and roots will emerge over the next few weeks. Before moving to a sunny spot in your garden, transplant the rooted cutting to a larger container and grow for a season.
Transplanting Hardy Hibiscus Plants
When moving Hardy hibiscus to a new location, be careful because it doesn’t take well to transplanting. When a hardy hibiscus has finished blooming in early fall, it is the best time to transplant it. To successfully move a hibiscus, good preparation is required.
First, in the new site, dig a massive hole. Next, reduce the hibiscus to about one-third of its current size. Dig 12 inches (30 cm) away from the root zone for every 1 inch (2.5 cm) of tree trunk for the next step.
Next, dig up the roots and the soil. Transport the hibiscus to the new spot and place it in the hole with a wheelbarrow. If the hole needs to be expanded, remember to do so. Fill the remaining area with soil from the hole, ensuring that the trunk’s soil line is level with the ground.
Press the hibiscus firmly into the ground, then water it well. Water the newly planted hibiscus every two to three days for the following few weeks.
How to Care for Hibiscus in Winter
In zones 4 through 9, Hardy perennial hibiscus plants die back in the winter and can withstand harsh winters. Prune the hibiscus stems back to just under one foot (30 cm) above the ground in preparation for winter. To protect the roots from freezing temperatures, add a thick layer of mulch over the root zone.
How to Get Rid of Pests that Affect Hardy Hibiscus Plant Growth
Hardy hibiscus plants are simple to maintain, however they may be infected by pests. To get rid of pests from hibiscus plants, spray with a neem oil solution. There is a total of 2 tsp. in the recipe. 1 tsp. of neem oil To make a bug spray, mix one quart (1 liter) of liquid Castile soap with one quart (1 liter) of water.
Spray both sides of the leaves thoroughly with a pump spray bottle, then leave to dry. For good pest control, spray neem oil weekly on your hibiscus plants. Mealybugs, spider mites, aphids, and whiteflies are all common pests that affect hibiscus plants.
Diseases Affecting Hibiscus Plant Growth
When caring for hardy hibiscus perennial plants, fungal diseases are the most common problems. Root rot can be caused by waterlogged soil. Flower buds that fall, yellow leaves, and leaf fall are all symptoms of hibiscus root rot. Powdery mildew can also be caused by too much moisture around the leaves. Watering the perennial properly is the best way to avoid diseases that affect hardy hibiscus. In the summer, water the blooming garden plant every week, while in the winter, only oncly.
FAQs About Hardy Hibiscus Care
Perennials are generally simple to maintain in Hardy hibiscus bushes. You simply have to watering the plant in hot weather to keep the soil moist, with little pruning required. Hardy Hibiscus Growth, on the other hand, can be affected by certain factors.
Does Hardy Hibiscus Come Back Every Year?
Perennials that bloom continuously from late summer until fall are known as cold-hardy hibiscus plants. In freezing temperatures, perennial hibiscus plants in the cold lose their leaves and die. After that, you can trim the stems down to approximately 4″ to 5″ (10 – 12 cm) protruding from the earth. In the late spring, Hibiscus will be back.
Why Are My Hibiscus Leaves Turning Yellow and Falling Off?
Hibiscus leaves may turn yellow as a result of watering problems: too much water or insufficient water. Drought is typically tolerated by Hardy Hibiscus, but parched soil can deplete nutrients from the foliage. Root rot and yellow hibiscus leaves can also be caused by overwatering or poor drainage. Make sure the soil is never soggy, even when it’s wet.
How Do I Keep My Hibiscus Blooming?
To keep your hardy hibiscus blooming all summer, water it frequently during warm weather. Just a day or two of Hibiscus blooms. The blooming shrub will bloom continuously in the summer and autumn when it is hydrated enough.
Why Are Hibiscus Flower Buds Dropping?
Hardy Hibiscus drops its flower buds and flowers because it lacks water. Although rose of Sharon and rose mallow buds can withstand drought, if the ground is dry or there is excessive heat, buds may begin to fall. During warm summers, ensure that the perennial hibiscus is watered well.
How to Get Rid of Fungus on Hibiscus Plants
Powdery mildew is a fungus that causes hibiscus leaves to turn grayish-white in color. Spray the leaves with a diluted milk solution or a baking soda spray to get rid of powdery mildew fungus. Always water the ground, not the leaves, to prevent fungus on hibiscus plants. Also, make sure that the plant is thriving in a location with sufficient air circulation for its thick leaves.