Hawaiian Hibiscus: Tropical Treasures

When you think of Hawaiian hibiscus, you’re probably thinking of relaxing on the beach with a drink in your hand the sound of waves and lush tropical greenery everywhere. Suddenly, it’s time for a vacation! If you need a little piece of tropical paradise in your home, you need to consider adding this beautiful plant to your garden.

“Hawaiian hibiscus” isn’t referring to just one type of hibiscus—it’s talking about seven species in the genus Hibiscus, as well as the Chinese hibiscus, which is a related type of flower but is not a native species to Hawaii. Oddly enough, the Chinese hibiscus is the most common ornamental species in Hawaii and is probably the kind of flower you’re picturing right now!

Hawaiian hibiscus needs warm temperatures to thrive, but you may still be able to grow these tall flowering species in your gardens, even if you live in colder areas. Planted as annuals or as house plants, you may also have moderate success provided that you give them summer-like conditions that mimic nature. Let’s get into how to grow these so you can start that Hawaii-style staycation as soon as possible!

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Quick Care Guide

Hawaii’s state official flower is Hibiscus brackenridgei. Source: D.Eickhoff

All About Hawaiian Hibiscus

Hibiscus arnottianus is a delicate pink and white confection of a flower. Source: bobmiller.1234

Hawaiian hibiscus is aptly named because they’re either native plants to or predominately grown in Hawaii. The yellow hibiscus flower, Hibiscus brackenridgei, is Hawaii’s official state flower. Unfortunately, this specific hibiscus flower, among a few others, is hard to find and is listed as endangered, which is a shame as this indigenous species produces gorgeous yellow Hawaiian hibiscus flowers!

The beautiful flowers are grown on bushy or tree-like flowering plants. If they’re grown in their natural habitat, they’ll grow to be a small tree. If they’re grown indoors or in cooler climates, they’ll grow to be small bushes. Depending on the specific hibiscus species, they’re either indigenous species or endemic to the Hawaiian islands, and likely won’t be found anywhere else unless someone put them there. 

The flowers come in several colors, including white, yellow, red, orange, and pink. Yellow hibiscus flowers are extremely rare. You could consider the shape of these flowers to be “iconic,” with their five or six flat petals that form a deep cone in the middle that has a long pistil sticking out of it. If you think they look like okra flowers, that’s because they’re in the same family: Malvaceae.

The flowers are most commonly used for leis, which are beautiful necklaces made with colorful flowers and are given to people for almost any occasion worth celebrating. They’re also used to make essential oils and are used in traditional medicine to treat various illnesses. The bark of Hibiscus tiliaceus, a red or yellow Hawaiian hibiscus, is used to make useful items like fishing lines, mats, and nets. The Chinese hibiscus has been used to make mascara.

Types Of Hawaiian Hibiscus

Hibiscus clayi is flamboyant and dramatic. Source: Starr

There are seven species of native hibiscus flower in Hawaii. They look similar and are all of the genus Hibiscus but some of them have slightly different attributes.

Hibiscus arnottianus, or the O’ahu white hibiscus, has white flowers that might turn pink toward the end of the day! It blooms all year long and is one of the few varieties that have a scent.

The official state flower, Hibiscus brackenridgei, boasts bright yellow flowers that will catch your eye if you can find it. This yellow Hawaiian hibiscus, referred to as ma’o hau-hele or pua aloalo in the Hawaiian language, is an endangered species that grow up to a towering 30 feet and only flowers in the winter and spring.

Hibiscus clayi has gorgeous red flowers and doesn’t have a scent. This one is easier to identify because its petals are slightly slimmer than the others.

Hibiscus furcellatus is a smaller native variety that usually only spreads out to 8 feet. It has elegant light purple and pink flowers that only last a day, but it can usually bloom all year long.

Hibiscus kokio is at risk of becoming an extremely rare native endangered species. It grows gorgeous orange and bright yellow flowers all year long. Just like the state flower, the bright yellow flowers on these native plants are harder to come by.

The bark of the Hibiscus tiliaceus has been put to use for mats, cordage, and a host of other handy items. It stands tall above the others, occasionally growing up to a whopping 50 feet! The flowers for this indigenous species are usually yellow or red.

Hibiscus waimeae is another native endangered species. It usually only grows up to 14 feet. This variety is good for shady areas since it’s more tolerant of shade than these other native plants.

Finally, there’s Hibiscus rosa-sinensis, the Chinese hibiscus. It’s not actually a Hawaiian hibiscus and was introduced into the Hawaiian landscape, but it’s the most popular hibiscus flower you’ll find on the islands. It’s often smaller than other varieties, produces pink, yellow, and red flowers, and only blooms in the summer.

Planting Hawaiian Hibiscus

Lavender-tinged Hibiscus furcellatus is a beautiful Hawaiian hibiscus. Source: Starr

Hawaiian hibiscus shouldn’t be difficult to grow if you’re able to provide the proper conditions for it. Ideal temperatures are USDA zones 9-11, but you can grow it as an annual in your backyard or as a house plant if you’re in colder areas.

If you have hibiscus seeds, start them indoors 10-14 weeks before the last frost date. Depending on where you live, this will likely be January or February. Your seedlings or store-bought starts can be transplanted outside after all dangers of frost have passed. If you’re going to grow it as an indoor plant, you can do it any time of year so long as the room is the ideal temperature.

Outdoor plants will ideally need access to at least six hours of sunlight each day, but they can also tolerate partial shade. Choose an area that’s protected from high winds, so the delicate blossoms don’t fall off of the tall, tree-like shrub. The soil should be slightly acidic, although it can tolerate neutral or somewhat alkaline soils.

To plant hibiscus seeds, you can soak them for eight hours to speed up the germination process, but this is unnecessary. Plant the seeds ¼-inch deep in potting mix. Keep its growing medium moist, and you should see a seedling emerge in 2-3 weeks. Seedlings should have access to sixteen hours of sunlight, and yes, grow lights will work perfectly! When seedlings have two sets of true leaves, you can move them to a bigger pot. Seedlings will need to be hardened off before they’re moved outside permanently.

If you’re planting transplants, wait for the late afternoon or a cloudy day to make the transition easier for the plant. Dig a hole for the root ball that’s deep enough for the top of the ball to be level with the ground’s surface. Cover the area with a couple of inches of mulch and keep it consistently moist as the plant acclimates to its new home.

Easy enough, right? Now let’s zoom in and look closer at the details.

Care

Hibiscus kokio subspecies saintjohnianus really stands out from the crowd. Source: Starr

As native plants to the main Hawaiian islands, these lovely flowering plants need a tropical environment. If you don’t have that, you can try to mimic it as much as you can to increase your chance of beautiful flower growth. It’s not as hard as you might expect!

Sun and Temperature

Hibiscus requires as much sun as possible, although they can tolerate partial shade. If you grow it indoors, it will benefit greatly from a grow light. Blooms develop when the temperature is 60-75°F (15-23°C).

Most Hawaiian hibiscus varieties are ideal for USDA hardiness zones 9-11, with the exception of the Chinese hibiscus that prefers zones 10-12, and the picky Hibiscus clayi that loves zone 11 specifically. 

This may sound discouraging if you live in cooler zones, but the lowest temperature in zone 9 is 20°F (-6°C), so these delicate flowers are actually pretty hardy despite their natural habitat in the Hawaiian islands! Daily temperatures shouldn’t drop below 55°F (12°C) for the best results.

Water and Humidity

While the genus Hibiscus can be drought-tolerant, they’ll look their best when you can keep the ground moist. Water it every day as long as the water can drain freely and not puddle up. Cut back on watering when the plant has stopped growing blooms during the winter months. They also like humidity, so indoor plants will benefit from being in the same room as a humidifier.

Soil

Hibiscus isn’t too picky when it comes to types of soils, as long as their growing medium has plenty of nutrients. A healthy dose of compost should give it everything it needs. They like slightly acidic conditions with a pH of 6-6.5, but can tolerate neutral or even slightly alkaline conditions if they must. Amend with the right pH adjusting amendment if it’s too acidic or alkaline.

Fertilizing

Hibiscus tiliaceus has a pinwheel-like petal pattern. Source: Starr

Healthy plants likely won’t require any fertilizing outside of additional compost a few times each year, but they will flower better if they have it. If you do need to use fertilizer, choose something that’s low in phosphorus, such as an NPK of 2-1-3 or something similar. Fertilize outdoor plants every 2-3 weeks, or once a month indoors. You don’t need to fertilize in the cool months.

Pruning

Pruning isn’t required, but it will keep your plant looking bushy and tamed, as well as prevent it from reaching tall tree heights. Prune your plant in the winter while it’s dormant, and it will create bushier growth in the upcoming season. Trim off leggy growth, branches that stick out too far for your liking, and extra twigs and stems you don’t want as you form it to the right shape for your landscape. Don’t be shy—they aren’t afraid of haircuts!

Propagation

Of course, this plant will produce seeds you can use to start new plants. Alternately, skip a few steps and take cuttings off of existing plants. Cuttings should be 3-5 inches from the strongest shoots available. Dip the cutting into a rooting hormone and place it in a pot with potting mix.

Keep the cutting consistently moist and make sure the plant receives plenty of sunlight. Avoid letting it get too cold or hot. After 3-5 weeks, the cutting should have a well-developed root system. You can transplant the cutting based on the recommendations we mentioned earlier.

Troubleshooting

Hibiscus waimeae is a true stunner. Source: Starr

You’re bound to have some issues with your hibiscus plant eventually. (It’s one of the many joys of gardening!) Here are some problems you should look out for.

Growing Problems

If you see yellow leaves that aren’t just your beautiful rare blooms, your plant is trying to tell you that something isn’t right. First, make sure there haven’t been any sudden changes in temperature, sunlight, or water. Did you move your plant to a new location? Did someone start “helping” with watering, and now it’s being overwatered? When was the last time you amended or fertilized? It may need some fertilizer. If it’s spring or fall, your plant may be transitioning along with the weather, and that’s perfectly normal.

If your plant is dropping buds and preventing you from seeing it flower, it may not be in the right temperature range. 60-75°F (15-23°C) is the ideal blooming temperature. It may also be a sign that the plant isn’t receiving enough light or water.

Pests

Aphids, mealybugs, thrips, and spider mites are small and, unfortunately, common pests that you might see. They feast on the sap of plants and can cause hibiscus plants to become stunted. Gently “power washing” these pests away with a hard spray of water can reduce their numbers, and insecticidal soap should take care of them. Neem oil is also effective. Ladybugs like to eat aphids and mealybugs for dinner, so try introducing some of those to your garden.

Japanese beetles like to eat leaves, stems, and flowers, and they’ll gobble up your plants if they’re given a chance. Fortunately, the small tree can handle quite a bit of damage before it affects them. Their larvae are white grubs that live in the ground and eat roots. The easiest way to get rid of them is to pick them off and kill them, but a specific species of beneficial nematodes (Heterorhabditis bacteriophora, often shortened to Hb) is very effective at hunting down and killing grubs in the soil. Milky spore powder has long been introduced to gardens to treat Japanese beetle species as well and might be an effective option.

Diseases

Root rot caused by fungi occurs when the ground is too wet and produces ideal conditions for fungal development. These fungi attack the root system of your ornamental, causing the roots to rot. Since these do love lots of available water to produce lushly green foliage and to flower, it’s easy to get carried away and risk damaging the roots. To prevent root rot in your gardens, make sure your growing medium is well-draining and doesn’t turn muddy or gloopy with excess water. If you’re prone to overwatering, try letting the top ½-inch of the ground dry out before watering again. Hibiscus is drought tolerant, so it won’t bother them too much.

Southern stem blight and leaf spots (particularly alternaria leaf spot) are fungal infections that affect the stems and leaves, respectively. You can prevent these with copper fungicides, but once they’re infected, there’s no universal cure. Remove damaged or infected foliage in your gardens, and monitor the rest where the infected plant was planted to ensure you’ve caught it before it spread. If an individual plant is seriously infected, remove the entire shrub to reduce the risk to others.

Viral diseases don’t have a cure and are often introduced to the garden by pests. Control pest populations and, if a virus infects one, remove that plant to prevent further spread to others.

Frequently Asked Questions

While notable, Hibiscus rosa-sinensis is not a native Hawaiian hibiscus. Source: Andres Hernandez S.

Q: Do Hawaiian hibiscus come back every year?

A: Hawaiian hibiscus are perennials when they’re grown in the proper conditions. They’re also perennial indoors or can be grown as annuals in colder climates.

Q: What hibiscus are native to Hawaii?

A: There are seven native species of these lovely ornamental plants that are native to the main Hawaiian islands. The official flower of Hawaii is among these, with beautiful yellow Hawaiian hibiscus flowers that are cheery and bright. Others, such as Chinese hibiscus, were introduced at some point and have become quite popular!

Q: How much sun does a Hawaiian hibiscus need?

A: The more, the merrier! They prefer full sun, at least six hours of direct sunlight each day, but they can tolerate partial shade if necessary.

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