Caring for & Growing Hardy Hibiscus Trees: Varieties, Transplanting

Do you want to spruce up your garden with some tropical vibes? If so, then we recommend that you try planting hardy hibiscus. The hibiscus has that tropical look and feel that will make any onlooker stop to appreciate its beauty. Hibiscus boasts of their large, brightly colored blooms and will instantly add impressive aesthetic appeal to any landscape. Now you may think that planting hibiscus in your garden is not ideal because you live in a location with colder climate. Don’t let that stop you as there is a variety of hibiscus that thrives in such weather conditions. It’s called hardy hibiscus.

It may not be known to a lot of people, but the hardy hibiscus has been a popular choice among gardeners in the northern parts of the U.S. for at least 100 years now. If you want to know more about the hardy hibiscus, the same way we’ve made a guide on sansevieria, including growing tips that can help to ensure the success of these showy plants, then continue reading.

An Overview

“Hardy hibiscus” is actually a general term for several types of species of the rose mallow group of the Malvaceae family (including their hybrids); which all belong to the same plant family as the typical tropical hibiscus. Compared to their tropical relatives, which are bred for warm temperate, tropical and subtropical regions, hardy hibiscus are bred for colder climate, thus the name – hardy. All of the few dozen species of hardy hibiscus blooms large, showy and pretty flowers that can grow to as much as 12 inches in diameter, although the average size of their flowers is usually 10 inches across. This earns them the title of being the plants with the largest perennial flowers in North America.

Hardy Hibiscus Perennial Flower Seeds, From Amazon

However, it should be taken into consideration that the genetic structure of individual species, cultivar, or hybrid, may not necessarily produce large flowers, instead they might even produce smaller ones. And that’s not the only issue you might observe because the color of their flowers can vary too! Color variations range from dynamic red, white with sometimes a shade of pink, purple and even the rare color blue.

There is one thing that all hardy hibiscus plants have in common and that is their flowers sport a burgundy or red-colored throats. In some cases, they feature streaks along the petals of the flowers that start from the inner petal all the way to the outer edges. Additionally, all hibiscus plants bear a familiar large and clearly visible staminal column in their center that’s covered with pollen.

Hardy hibiscus can grow between 2 ft. – 10 ft. tall depending on which variety you have. In warmer areas in the United States, all types of hardy hibiscus can bloom as early as June; however, in the colder areas, they usually start to bloom around August and will continue to bloom until winter starts. In the science of taxonomy, all plant varieties of the hardy hibiscus are classified as Hibiscus moscheutos. But gardeners often refer to them as “rose mallows” or “swamp mallows.”

Every summer all hibiscus varieties will appear woody and may look similar to dwarf shrubs, but when the winter comes, the leaves and the stems fall and die, therefore we can consider the hibiscus as a herbaceous perennial plant.

History

According to some estimates, the hardy hibiscus has been around since the early 20th century. Breeders of plants reported developing hybrids of the tropical hibiscus in order for them to survive in colder climate.

The owner of Fleming Flower, Gretchen Zwetzig, said that from memory she can recall hardy hibiscus only started to become common around the 1950s. She would be in her own right to mention this, because her company is one of the oldest in the flower breeding industry.

One of the first modern cultivators of hardy hibiscus is a man by the name of Robert Darby. His development of the first two hibiscus hybrids was a success. He cross-bred at least four native species of hibiscus that created the Lord and Lady Baltimore hybrids (H. laevvis, H. palustris, H. coccineus, and Hibiscus moscheutos). These hybrids are still famous among gardeners even to this day.

Meanwhile, in Japan the Sakata Seed Corporation also started their hibiscus hybridization program that produced the H. Dixie Belle and the H. Southern Belle varieties in the 1960s. Then by the 1970s the Disco Belle series was also successfully developed.

Fleming Flower also further developed more hybrid varieties such as the Plum Crazy, Torchy, Dream Catcher, Old Yella, Kopper King, Fantasia, Fireball, and Robert Fleming

Planting and Care Requirements

If you want to successfully grow the hardy hibiscus in your garden, then you need to learn how to care for it properly, especially its flowers. Today we will give you adequate and accurate information on how to properly plant and grow healthy herbaceous perennials known as hardy hibiscus.

Seed Planting

  • If you want to plant hardy hibiscus from seeds indoors and if you live in Zone 6 or lower, then you may want to pick a date 3 months prior to the start of the frost.
  • People located in Zone 7 or a warmer region can start to grow their seeds indoors about 1 – 2 months before the last average frost date, or you can also sow plant the seeds in the soil directly after the frost has subsided.
  • To maximize on your seeds’ potential, ensure that they are soaked in water for a 12-hour period before you plant them. This rule applies to both outdoor and indoor planting.
  • Burry the seeds about half-an-inch deep into the soil. For outdoor planting, begin training the plants to be hardened during the last frost date by exposing them to the elements (e.g. sunlight and wind) when favorable weather conditions exist.
  • On the first day of growing them, take them outside and allow them to be exposed to the elements for about 30 minutes, then increase the time of exposure to 1 hour a day for an additional 5 days prior to transplanting them to your garden.

Choosing and Preparing a Location

  • Hardy hibiscus grows best in half-wet to wet soil that drains well. Make sure that the soil is not too heavy, but these plants will not survive in sandy, dry, or poor-draining soils.
  • You can mitigate this problem by mixing 1 – 3 inches of organic compost before planting the hardy hibiscus.
  • If you live in Zones 4 – 6 which has a colder temperature, you should plant the hardy hibiscus on the south side of your garden, as it is the place where they’ll get plenty of sunlight and be protected from the winds.
  • For those of you who live in warmer regions where you get 6 hours of sunlight each day, then the hardy hibiscus is also ideal there; however, their legs may not be as thick and healthy as they normally should and their blooms will not be as healthy as well, or they may not bloom at all.

Watering

Hardy hibiscus typically grows in swamp and damp areas. With the hybrid varieties their need for water has been significantly reduced. This does not mean that they don’t need an adequate amount of water to survive anymore. Make sure to dampen the soil where you planted the hardy hibiscus, but don’t pour too much water to it, because it could cause its roots to rot and the plant will die. It is the leaves that are consuming most of the water in the plant, so with smaller hibiscus with less leaves will need less water compared to larger plants with more leaves. Make sure to water the hardy hibiscus daily while it is in its growing season.

Feeding Requirements

Aside from water the hardy hibiscus also need plenty of nutrients while they’re growing. We recommend that you feed them with a water-soluble or slow-release fertilizer in order to maximize their chances of getting the nutrients they need. But like everything else, do not overfeed them, as this can lead to high toxicity in the soil and it could result in the demise of the plant later on. Feeding your hardy hibiscus a 10-10-10 or a 20-20-20 fertilizer will yield the best results. Other types of fertilizer you can feed your plants with include a diluted liquid fertilizer done each week, or use the slow-release fertilizer 4 times a year, applying it once every season.

Make sure to also read our guide on caring for anthurium plants.

Pruning Hardy Hibiscus For The Winter

The hardy hibiscus is a herbaceous perennial and it sheds its leaves during the winter. You can prune it in the fall even if its branches look healthy – it will just grow its branches and leaves back in time.

Cold Weather Care

If you live in or around the frigid zone where the temperatures falls between 0 to -50 in the winter, you’ll need to take extra precaution to protect your hardy hibiscus and ensure they survive. There are a few ways to do this and one of them is to apple 3 – 4 inches of fresh mulch to the plant around the root area. Do this after pruning the flowers and leaves to protect the roots from getting frozen. Other things you can use to shield the roots of the hibiscus is to use wood chips, leaves, or straw.

The hardy hibiscus should grow back its leaves and flowers by spring (assuming proper protection is applied). However, you need to be a little patient, as the hardy hibiscus grows back their leaves at a much later time than most plants. Around May or June you should be able to see the first signs of their new growth, but this will still depend on the climate in your area.

Pests and Diseases

Just like most plants, the hardy hibiscus is also susceptible to pests and disease. Some large animals find the leaves of the hibiscus palatable like the deer – they will munch on it until it becomes bare. You can build a fence around the hardy hibiscus to keep the deer away. Aphids also can also destroy the leaves, the stems, and the flowers of your hibiscus, as they too like to eat these plants. Use insecticidal soaps and oils to deal with them and prevent them from causing further damage. Your hardy hibiscus is vulnerable to fungal infections too! This includes rust, leaf spot, and botrytis blight; however, it’s easier to avoid this than with aphids and you only need to avoid pouring water on the leaves when you water them.

Outdoor Hibiscus Care: Tips on Growing Hibiscus in Gardens

What makes any plant worth having in your garden is its flowers and the hibiscus features stunningly large, bell-shaped flowers. The tropical hibiscus is usually grown indoors, but the hybrid hardy hibiscus can be planted in your garden. Get to know more about the difference between hardy hibiscus and tropical hibiscus, as well as how you can grow them in your garden.

Hardy Hibiscus vs. Tropical Hibiscus

While their flowers may appear similar – simply because the hardy hibiscus is, in fact, a hybrid – they are very different from the tropical hibiscus that is fussy and grown in hothouses. The USDA classified the hardy hibiscus as a non-tropical plant that can withstand extreme cold temperatures as far north as Zone 4 (provided the plant is given enough protection). Meanwhile the tropical hibiscus maximum tolerance to the cold is anywhere north of Zone 9. Tropical hibiscus can be purchased in single or double blooms and in color variations such as yellow, orange, peach, or salmon. The hardy hibiscus, on the other hand, is only available in single blooms, with colors ranging from red, pink or white.

The leaves of the tropical hibiscus have a dark green color and glossy texture, while the hardy hibiscus sports a heart-shaped leaves and have a lighter green color. Hardy hibiscus will surprise you because they’re very easy to grow and all you have to do is just plant them in a well-drained soil and a spot where they can get more than 5 hours of sunlight each day. In order to successfully grow the hibiscus is to water the plant daily and keep the soil moist appropriately. The hardy hibiscus will grow even if you won’t apply fertilizer; however, applying fertilizer will make the plant healthier and cause it to bloom regularly.

You may notice that your hibiscus will die when the autumn frost comes, but don’t worry and simply cut the whole main stem down near the roots to about 4 or 5 inches (10-13 cm.) above the ground. When spring will come it’ll just regrow itself and have thick leaves, as well as bloom.

Planting – How Hibiscus Arrives

When you order your hardy hibiscus online and it arrives via a delivery service, it might simply look like a pot of soil with sticks. Don’t let this disappoint you because underneath the soil is a strong and steadily growing root. The hibiscus has yet to grow and is lying in dormant at the moment. You’ll need to follow the instructions below if you are to grow your hardy hibiscus successfully.

Planting Needs

The optimal survivability of the hardy hibiscus is in well-drained soil that’s rich with organic materials. This plant wants to be in acidic soil and in order to make your soil acidic, just add peat moss potting soil. Make a raised bed for the plant if the soil in your garden is mostly clay – this helps prevent any water buildup. When the threat of the frost has passed that is when you should plant the hardy hibiscus. To plant, just dig a hole that’s twice the size of the pot where the hibiscus came in with, then place it in the hole you just dug and make sure that the crown rest at ground level or roughly an inch above it.

Press the newly loose soil back into the roots of the plant and water it. If some of the soil near the base washes away when you water it, add more soil. Make sure to plant each hibiscus 2 – 3 ft. apart if you opt to plant several of them in your garden. Even though it may seem small, it actually grows to 48 – 72 inches tall!

Location and Light

Hardy hibiscus usually emerges at a later time than other plants even in cold springs or early summers, so try to be patient. It will grow at its healthiest when it receives full sunlight. They’ll still grow in a partially shaded area, but it will stifle their growth and they might not bloom as often as they would. If you reside in a region where summers are often very hot, you may want to put some shade over your hibiscus to keep it from dying. When you plan the layout for your garden, make sure that the hardy hibiscus is planted along, or in the next row of perennial flower beds.

After Planting Care for Years of Growth

Fertilizer

The hardy hibiscus can live off of the nutrients of the garden soil, but it wouldn’t hurt if you feed them some good fertilizer. During the spring you can apply a layer of compost around its base to make the soil healthy. You can also use 10-4-12, 9-3-13 or 10-10-10 on the same area too! Just make sure to follow instructions, especially on the exact amount of fertilizer to use. For example, too much phosphorous is lethal to the plant.

Temperature

The hardy hibiscus is able to survive and thrive even in Zones 4 and 5. But it mostly depends on warm temperatures for blooming, during fall, winter and cold spring its growth is slow. Add a layer of mulch around the base of the hardy hibiscus to protect it during winter.

Watering

Hibiscus loves well-moisted and well-drained soil. Not watering your hardy hibiscus daily will cause it to dry out and will shed its leaves until it will just look like a bunch of dead sticks. But not to worry, because it’s not dead yet and this is just a defense mechanism for the plan to protect its roots – it will re-bud again, just be patient. Just be mindful about your watering activities and not overdo it or neglect the plant. In case, your hardy hibiscus is in a pot, then ensure that you punch holes, or the clay pot already has holes in it for adequate drainage. Keeping the water in the pot for too long will cause root rot and kill the plant eventually.

Pruning

There’s no real need for the hardy hibiscus to be pruned, but still you may want to prune them to make beautiful shapes for landscaping benefits. This hibiscus is a herbaceous plant and it sheds its foliage every fall only to regrow it in late spring or summer. If you want your hibiscus to branch out and grow more flower stalks, then simply prune them in early summer when it’s at the beginning of its growth.

Propagation

The best way to propagate hardy hibiscus is by seed, stem cuttings, or crown division.

From Seed

The most economical way to grow plants is from seeds; however, it might be impossible to know what kind of plant you’ll get if the seeds are from a hybrid variant. But it’s not a disadvantage, especially if you’re looking for variety. Seeds should be grown in a hothouse 3 months prior to the last frost date in Zone 6, or in colder regions. But in Zone 7 or warmer areas, you may begin growing them about 1 – 2 months prior to the last frost date or you can also sow them directly in your garden once the frost has passed.

Remember to soak the seeds first before planting them and dig 1/2-inch deep into the soil to sow the seeds. Keep the seeds at 50 to 60% humidity if you’re going to plant them in flats, keep also in full sun. When the frost is almost over, begin hardening them off by slowly letting them out in the sun and wind if there’s favorable weather, you may start off with half-an-hour on the first day, then add 1 hour for each succeeding day for 5 days before transplanting them to the garden.

From Cuttings

The most ideal time to take cuttings for the hardy hibiscus is during spring or early summer, do it prior to its time to bloom.

This is how it is done:

  1. Get an empty pot and pour in a mix of 50% perlite and 50% soilless potting, then moist it.
  2. Cut a piece of new growth from the fully grown hibiscus (softwood) about 4 – 6 inches long.
  3. Clear all the buds from the lower half of the piece you’ve cut, moisten the edge of the cut end, and dip it in rooting hormone powder for softwood. Make sure that the powder does not get wet before you dip the softwood.
  4. Get a 1-foot long stick that’s twice or 3 times as thick as the entire diameter of the softwood and poke it into the pot where you’ve prepared the growing medium earlier. Make the hole as deep as half the length of the softwood too! Then insert the lower half of the softwood with extreme care so as not to rub off the rooting powder and press the growing medium into the softwood.
  5. Put the pot where you’ve planted the softwood hibiscus in an area with a consistent temperature of 15.6 °C (60 °F) , or in a greenhouse with about 50% – 60% humidity, or by your window where it can get enough sunlight. Just make sure that it’s covered with a humidity bag or cover.
  6. Water the softwood cut regularly and add about 1% – 3% hydrogen peroxide in the water. The hydrogen peroxide will reduce the chance of the softwood cut from rotting.

You should be able to see new leaves sprouting in about 2 months, if all goes well. Check the bottom of the pot to see if the roots have creeped out, as this is an indication that you need to transplant it into a new pot as the softwood cutting hibiscus is already well-rooted. Use a 10 or 12-inch plastic container and remove it from the greenhouse and into a sunny window throughout the spring before you transplant it to your garden.

From Crown Divisions

If you want to do crown divisions, then you must select the best hardy hibiscus that’s already mature, fully grown and have lots of stems and healthy roots. Around spring or early fall are the best times to make crown divisions on your hibiscus. This is because the soil is moist and is ideal for this method of propagation. You should carefully divide your hardy hibiscus, because they’re not like some perennial plants and their root system must not be dug up, or else it will suffer permanently. Most plants that are grown from cuttings typically grow shallow roots also; however, if you avoid disturbing their roots from the start, then your hardy hibiscus should be fine.

Do these things in order to carry out divisions:

Step 1: push out any mulch away from the base of the plant, so it can be used again.

Step 2: get a tape measure and mark 12 inches from the base of the plant going outward and dig about 2 feet down parallel to its roots, or deeper if necessary in order to lift up a small portion of the plant along with a few stems.

Step 3: Be careful not to damage the taproot as you remove smaller roots.

Step 4: Get a sharp garden knife and use it to cut a piece of the root mass that’s connected to the stems you want to divide from the plant (always keep in mind to exercise caution so as to avoid damaging the roots).

Step 5: Cut away dead roots and plant the section of the hardy hibiscus that you’ve divided from the main plant, or you can also temporarily pot it and use transplant fertilizer and allow it to grow for a few months before transplanting it to your garden again.

Growing Tips

  • Water the hardy hibiscus daily until it has fully matured
  • Apply mulch to protect the plant, especially during the hottest and coldest times of the year
  • Feed the hibiscus with a fertilizer that’s high in phosphorus (skip this tip if the soil is already rich with this nutrient)
  • Install shade to protect from winds in colder regions
  • Even though the hardy hibiscus has a high tolerance when it comes to moist soil, do plant them in a well-drained soil in order to avoid root rot from waterlogging.
  • The hardy hibiscus enjoys growing in full sunlight; however, you may want to put them in shaded areas if you live in warmer areas.

Varieties to Consider

Based on your climate, space availability, and aesthetic preferences, there are dozens of cultivars that you can choose from now. For your consideration, take a look at some of them below:

Kopper King

Kopper King is a compact, vigorous, sturdy that has a dark burgundy foliage with large, light pink to nearly white flowers hibiscus cultivar. It can grow to 3 – 4 feet tall with a 4 – 5 feet spread. Hardy in Zones 5 – 10.

Lord Baltimore

Lord Baltimore is a vigorous, sturdy, shrubby cultivar that can grow up to 4 – 5 feet tall with deeply-cut, irregularly serrated, glossy dark green leaves and flowers the size of a dinner plate. Hardy in Zones 5 – 9, Lord Baltimore is the favorite among garden enthusiasts.

Lady Baltimore

Valued for its late summer display, Lady Baltimore has large, pink, dark-throated flowers with green foliage. It features beautiful pink blooms that are 5 – 6 inches in diameter with satiny, red centers and ruffled petals. It can grow up to 5 feet in height and has about the same spread. Hardy in Zones 5 – 10.

Midnight Marvel

Huge, pure red blooms absolutely glow against the richest purple maple-leaf-like foliage in the genus. It sports a glossy, black-red buds which open to 8-9 inches, deep scarlet red flowers. It can grow up to 3 – 4 feet in height with a wide 4 – 5 feet spread. The Midnight Marvel thrives in moist-rich soil, but is able to survive even in dryer, poor conditions. Hardy in Zones 4 – 10.

Terri’s Pink

Terri’s Pink is a vigorous perennial Hibiscus with deciduous foliage and deep pinkish-red saucer-shaped blooms that are 6 – 8 inches wide. It grows to an amazing height of 6 – 8 feet tall with a 4 – 6 feet spread and is hardy in Zones 7 – 11.

Transplanting

When you want to transplant a Hardy Hibiscus, it’s important that you take care of the roots in the process so that they don’t get damaged, which is a combination of supporting the plant as you are moving it, as well as timing it correctly with the plant’s flowering.

When the flowers start fading, that is the best time to move the plant, which means you likely won’t be able to do it before September, at least in most parts of the country. When the plant has been moved, that is the time when it is most prone to getting damaged, why you will want to ensure that the plant also has some time in their new home (the soil that they have been moved to), before the really harsh winter conditions set in – you don’t want it to be exposed to freezing conditions before it has gotten used to its new home.

As you are getting ready to dig up the plant, you will want to make sure that you are getting a lot of the root system moved over to the new place as well. Fr every inch of trunk, you will want to be digging up 1 feet around the plant in a circle, why it is no surprise that it will be a bigger project to get this moved the bigger the plant is. The radius of the circle that you are digging up will therefore be 1 foot for a plant with a 1 inch trunk. In order to separate the root ball from the soil, you will want to drive a shovel underneath the roots, however, it’s important to make sure that you are doing the digging properly.

You cannot dig within a foot per inch of trunk of the plant, so you will need to dig up the soil outside of that radius, and as you have dug up that soil, you are now ready to drive the shovel under the roots.

The entire digging process is easier to do, make sure to moisten the soil beforehand. It’s important to know that your Hardy Hibiscus can be damaged in the process of moving it if you aren’t careful. You will want to transport it as delicately as possible, why you won’t simply be carrying it, especially if it’s being moved a significant distance. The easiest solution is for you to use a wheelbarrow to move it, and as you’re lifting the plant you will want to lift from under the root ball which offers additional protection.

As you’re putting the Hibiscus back in the soil, now at its new location, you will want the top of the soil to be even with the surrounding soil, as you don’t want the trunk to start rotting from the plant being planted too low.

While we hope you enjoyed this article on caring for Hardy Hibiscus trees and bushes, we’d also like to take a moment to advertise some of the tools that we sell on this site, including waste oil heaters, which can provide a great way of saving money if you have ready access to waste oils. If you have a lot of trees on your property, you may also be interested in our wide belt sanders. Or, if you are generally a person who likes doing DIY work and have a truck, a lot of people enjoy the fuel transfer tanks, that can give your truck the fuel it needs, or our engine driven welders or plasma cutters, if you like doing metal work. On the topic of engines, we also have an article dedicated to Thermo King alarm fault codes or how to detect a bad IAC valve, if that has any interest.

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