If you’re a hibiscus enthusiast, you know the joy of seeing your plants burst into stunning blooms. But what do you do when your perennial hibiscus plants refuse to show off their vibrant flowers? Don’t worry, we’ve got you covered. In this article, you’ll learn how to get your hibiscus plants to bloom with seven proven tips that are sure to impress even the most stubborn varieties. Follow our tips and you’ll be admiring your gorgeous hibiscus flowers in no time at all!
Lets start by getting to know the different varieties of hibiscus. Hibiscus plants are known for their colorful flowers and are one of the most recognizable tropical species of plant around the world. The term hibiscus, however, can refer many different species, some of which are perennial and some are annual. This is important because it tells you a lot about the growth and flowering of your hibiscus plant.
Is my hibiscus perennial or annual?
Perennial plants are plants that live for two or more years. They have a longer life cycle and they usually have a deeper root system that allows them to survive harsh weather conditions and drought. They can grow and produce flowers and fruits for several years.
Annual plants are plants that complete their life cycle in one growing season. They grow from seed, produce flowers and fruits, and die within one year. This means they need to be replanted every year to maintain a continuous supply of flowers. They usually have a shallow root system that makes them more susceptible to drought and other environmental stresses.
In this article we’re going to cover the Hibiscus rosa-sinensis and hibiscus hybrids. Both are tropical plants that grow in warm climates. If you need help with your dinner plate hibiscus (Hibiscus moscheutos) we’ve got a comprehensive guide which shows you how to grow amazing large flowers on hardy hibiscus plants.
| Common Name | Hibiscus Species | Perennial/Annual |
|---|---|---|
| Hardy Hibiscus | Hibiscus moscheutos | Perennial |
| Roselle | Hibiscus sabdariffa | Annual or Perennial |
| Tropical Hibiscus | Hibiscus rosa-sinensis | Perennial |
| Tropical Hibiscus | Hibiscus hybrid | Annual or Perennial |
Understanding the blooming process of hibiscus plants
When you understand the blooming process you are better at troubleshooting flower production issues. The flower production cycle for tropical hibiscus plants consists of the following stages:
Bud formation
Flower buds typically start to form on Hibiscus rosa-sinensis in late winter or early spring, when the days start to get longer and the temperatures begin to warm up. However, the timing of bud formation can vary depending on the cultivar and growing conditions.
Flower appearance
Once the buds have formed, it can take several weeks for the flowers to appear. The timing of flower appearance can depend on factors such as temperature, light, and humidity, but you should start to see them by late spring or early summer.
Flower duration
The flowers of Hibiscus rosa-sinensis can last for several days to several weeks, depending on the cultivar and growing conditions. After the flowers have bloomed, they will eventually drop off the plant. This can be a natural part of the flower production cycle, but excessive flower drop can be a sign of stress or disease.
How to get hibiscus to bloom all summer
To unlock the secrets to getting your hibiscus plants to bloom, it’s essential to consider the factors that can impact their blooming. These factors include the soil, sunlight, temperature, fertilizers, and the pests and diseases that can hinder their blooming process. By understanding and managing these factors, you’ll be well on your way to a blooming hibiscus garden.
Now, let’s dive into the seven proven tips that will help you get your hibiscus plants to bloom like never before.
The most important factor in hibiscus flowering is sunlight
If your hibiscus isn’t blooming the most likely reason is that it’s not getting enough light. Hibiscus plants thrive in bright, direct sunlight. However, too much direct sunlight can cause the leaves to turn yellow and fall off, so some shade during the hottest part of the day might be beneficial. On the other hand, insufficient sunlight can result in weak and spindly growth with fewer flowers.
To strike the right balance, aim to provide your hibiscus plants with at least six hours of full sun exposure each day. If you live in a particularly hot climate, consider providing full or partial shade during the hottest part of the day. This will help to protect your plants from the scorching sun.
If you are growing your hibiscus plant indoors you’ll need to place it right up next to a window that gets full sun. If this isn’t an option for you then you’ll need to provide the equivalent of full sunlight with a grow light. Observing your plants and managing their sun exposure is the first step in promoting flower formation.
Feeding is the next most important strategy for hibiscus flower production
Once you know that your hibiscus plant is getting enough sunlight, the next step is to make sure it isn’t starving. Just like a balanced diet fuels our bodies, the right nutrients fuel your hibiscus blooms.
When you are shopping for fertilizer you will see a set of three numbers, or the NPK ratio on the packaging. This refers to the relative concentrations of nitrogen (N), phosphorus (P) and potassium (K) in the fertilizer. Nitrogen is for foliage production, phosphorus for flower and fruit production and potassium for root and stem growth. If you’ve got a fertilizer that is too high in nitrogen you’ll get lots of foliage produced at the expense of flowers.
When you are targeting flower production you should opt for a balanced fertilizer with a higher phosphorus content. That’s because phosphorus is the secret ingredient for flowering magic.
Which fertilizers are best for hibiscus flowers?
During the growing season, feed your hibiscus every 4-6 weeks for granular fertilizers, or every 2 weeks for liquid fertilizer. But remember, moderation is key – over-fertilizing can lead to lush foliage but fewer blooms. Make sure you check the manufacturer directions and apply the correct dosage and frequency, especially if you are using a slow-release fertilizer.
For super-healthy hibiscus plants you’ll want to supplement with a tonic as well as a fertilizer. Think of the tonic as the multivitamin and the fertilizer as the food. Tonics have ingredients like seaweed, beneficial bacteria and fungi that will nourish the soil and your plant.
Maintain optimal moisture
Flower production requires consistently moist soil so make sure your plants get a good deep soak with plenty of water in hot dry weather. If the soil dries out they will drop their buds to conserve moisture and energy and you’ll miss out on all those gorgeous flowers. When you water, make sure it’s thorough, allowing the water to penetrate deep into the soil. Water the base of the plant rather than the leaves
To maintain this hydration harmony, consider mulching around your plants. Mulch acts like a moisture-saving blanket, helping the soil retain water and reducing the need for frequent watering. As you tend to your hibiscus, observe their leaves – if they start to droop, it’s a subtle cue that they’re thirsty.
As plants enter their winter dormant period they will need less water. This is also the time that you stop applying fertilizer.
By mastering the art of watering, you’ll ensure that your hibiscus are hydrated and ready to burst into bloom when the time comes.
Provide the perfect growing environment
Start by choosing a spot that’s a sun-soaked paradise. Being tropical plants, hibiscus don’t like the cold and will appreciate a nice warm position in your garden. The optimal temperature range for tropical hibiscus to bloom is between 16 and 27 oC or 60 and 80 oF.
Extreme weather can also throw a curveball, so be mindful of protecting your hibiscus from late frost if you are in colder climates. Similarly, it’s a good idea to watch out for scorching heat and hot strong winds in late summer for those in dry climates. Make sure your hibiscus is well watered during periods of intense heat.
As we’ve already established, hibiscus thrive on sunlight, so aim for at least six hours of direct sunshine each day. And when it comes to garden soil, think of it as the foundation of your hibiscus haven. You’ll get the best results growing your hibiscus plants in a well-drained soil enriched with compost or organic matter. A rich soil ensures that your plants receive the nutrients they need and good drainage is essential for avoiding waterlogged roots. This is important because roots that are sitting in over-wet soil are deprived of oxygen, which can cause bud drop and flower drop.
Don’t forget to check your soil pH
If you have the sunlight, food and water covered but your hibiscus still isn’t flourishing it’s worth checking the pH of the water and the soil.
- Soil pH: Hibiscus rosa-sinensis prefers a slightly acidic to neutral soil pH between 6.0 and 7.0. Soil pH outside of this range can affect the plant’s ability to absorb nutrients and lead to poor growth and flowering.
- Water pH: The pH of the water used to irrigate Hibiscus rosa-sinensis can also affect the plant’s growth and flowering. According to a study on alkalinity-induced responses in hibiscus cultivars, increasing the concentration of NaHCO3 in the water can cause an increase in growing medium pH, which can affect the plant’s growth and development.
Pruning techniques for extra blooms
Imagine your hibiscus plants getting a stylish makeover, their branches rejuvenated and their blooms reaching for the sky. Think of pruning as an artistic endeavor, where each snip contributes to the masterpiece your hibiscus will become. With your pruning shears in hand, you’re ready to shape your hibiscus into a living work of floral art. Pruning might sound like a daunting task, but it’s the key to sculpting your hibiscus into blooming wonders.
Begin by removing dead or weak branches – this not only enhances the plant’s appearance but also directs energy to new growth. Later, when the blooming season wraps up, consider a more dramatic prune. Cut your plant back by about one-third of the plant’s height. This encourages fresh growth and sets the stage for the next blooming cycle.
Pruning is important for maintaining the shape and size of the plant, but improper pruning can reduce flowering and damage the plant. It is important to prune the plant in late winter or early spring before new growth appears and to avoid cutting back more than one-third of the plant at a time
Hardcore tip: Use a growth retardant.
It might seem strange to use a growth retardant to promote flowering but stay with me here. Growth retardants, or plant growth regulators (PGRs) reduce the stem length which means that plants then have more energy to put into flowering instead of increasing their size and foliage surface area. This is a secret technique used in the horticulture industry to get plants looking their best for display at your local garden center.
Not all growth retardants will have the same effect though. Some will delay flowering so it’s important that for hibiscus flowers you use a PGR with uniconazole as the active ingredient. Look for product names Sumagic or Concise in the USA or Sunny in Australia. Remember, it’s a chemical so you need to make sure you read all the instructions and precautions before you use it. This one definitely needs to be kept away from waterways so be extremely careful if you are using it outdoors.
Overcoming common pests and diseases
While your journey to abundant blooms is exciting, there might be a few bumps along the way. Keep an eye out for these pests and diseases so that you can get on top of them early and protect your hibiscus plants. All of the pests below can be treated with a product such as a white oil spray . Other pesticides like insecticidal soap will work too.
Aphids
Aphids are small, soft-bodied insects that suck the sap from the leaves and stems of the plant. They can cause the leaves to curl and distort and can transmit viruses.
Spider mites
Spider mites are tiny pests that feed on the undersides of the leaves, causing yellowing and stippling. They can also produce webbing that covers the leaves and stems.
Mealybugs
Mealybugs are small, white, cottony insects that feed on the sap of the plant. They can cause stunted growth, yellowing, and leaf drop.
Scale insects
Scale insects are small, immobile pests that attach themselves to the stems and leaves of the plant. They can cause yellowing, wilting, and leaf or bud drop.
Powdery Mildew
Powdery mildew is a fungal disease that appears as a white, powdery coating on the leaves and stems of the plant. It can cause stunted growth, yellow leaves and eventually leaf drop.
Other Hibiscus Diseases
Root rot: Root rot is a fungal disease that affects the roots of the plant, causing them to rot and die. It is often caused by overwatering or poorly draining soil. If you have experienced heavy rain and your plants are at risk you can help to protect them with a systemic fungicide.
Leaf curl disease: Leaf curl disease is a viral disease that causes severe leaf curling, vein thickening, and enation (a bubbly or bumpy texture on the leaf). It is caused by Cotton leaf curl Multan virus and has been reported to affect Hibiscus rosa-sinensis in India.
What next?
As you stand amidst your garden, envision your hibiscus blooms in all their glory – a testament to your dedication and care. By following these seven easy steps, you’ve embarked on a journey that transcends gardening; it’s a connection with nature’s vibrant beauty.
Each choice you’ve made, from selecting varieties to nurturing the perfect environment, has woven a tapestry of blooms that will paint your garden with splendor. Your hibiscus will reward your efforts with a breathtaking display, an invitation for you to immerse yourself in the wonder of the natural world.
So go ahead, celebrate the transformation of your garden into a haven of hibiscus blooms – a living testament to your blooming success. May your hibiscus journey continue to bloom and flourish, as you revel in the beauty you’ve cultivated with love and knowledge.
Frequently Asked Questions
What month do hibiscus bloom?
In tropical climates a tropical hibiscus plant can bloom all year round. In cooler climates they will bloom from late spring to early fall. In the northern hemisphere they will bloom from May through to September or October, and in the southern hemisphere from November to March or April.
Do you deadhead hibiscus flowers?
Yes! Use clean sharp pruning shears or secateurs to snip the wilted and faded flowers. This will encourage new buds to form and you’ll be rewarded with a flush of new flowers.
Should hibiscus be cut back?
Yes, cut them back by about a third when they finish flowering in the fall.
Does Epsom salt help hibiscus bloom?
Maybe. If your soil is low in magnesium then yes, Epsom salt will help your hibiscus bloom. Magnesium is important for chlorophyll production, and chlorophyll is what gives leaves their green color. Healthy leaves give hibiscus plants the energy they need to produce flowers. If you plant has nice dark green healthy leaves it doesn’t need Epsom salts. If it has pale green or yellow leaves it may benefit from Epsom salt.
How do I know if I have a perennial hibiscus?
A perennial hibiscus has woody stems and it’s leaves will be larger and more lobed than an annual hibiscus. They will survive winters and put on new growth in the spring. An annual hibuscus will have softer green stems, smaller leaves and flowers, and will die off in fall or early winter.
How long do hibiscus plants live?
A perennial hibiscus plant can live up to 50 years however the newer hybrid varieties have a shorter lifespan and may only live for around five years.
What’s the lowest temperature a tropical hibiscus can tolerate?
It’s best to maintain a temperature of at least 55 oF or 13 oC. Tropical hibiscus plants can tolerate brief periods lower than this temperature but will sustain damage. As temperatures approach freezing the plant is unlikely to recover from damage.
Can I bring my potted hibiscus in for the winter?
Yes! Please do if you live in a cold climate. Make sure it is getting lots of light by putting it close to a large window. In the northern hemisphere a south facing window is best and in the southern hemisphere choose a north facing window. If this isn’t an option for you consider investing in a grow light. You might even be rewarded with flowers if you can keep it happy!
Still have questions?
Are there concerns that were not addressed here? We’re here to help.
References
Knox, G.W., & Schoellhorn, R.K. (2019). Hardy Hibiscus for Florida Landscapes. EDIS. https://journals.flvc.org/edis/article/view/115144
Nazarudin, A. (2012). PLANT GROWTH RETARDANTS EFFECT ON GROWTH AND FLOWERING OF POTTED Hibiscus rosa-sinensis L. https://www.semanticscholar.org/paper/PLANT-GROWTH-RETARDANTS-EFFECT-ON-GROWTH-AND-OF-L.-Nazarudin/ff8da6d42a71cfe06eb51a67b96d2f73b091bda5
Pounders, C.T., & Sakhanokho, H.F. (2014). ‘USS Alabama’, ‘USS Mississippi’, ‘USS Missouri’, ‘USS Tennessee’, and ‘USS Texas’ Chinese Hibiscus (Hibiscus rosa-sinensis L.). Hortscience, 49, 1467-1469. https://www.semanticscholar.org/paper/%E2%80%98USS-Alabama%E2%80%99%2C-%E2%80%98USS-Mississippi%E2%80%99%2C-%E2%80%98USS-Missouri%E2%80%99%2C-Pounders-Sakhanokho/641bc596ac796d0cd9f4ea56ac82fcd3b21061fb
Pounders, C.T., & Sakhanokho, H.F. (2012). ‘USS Arizona’ and ‘USS California’ Tropical Hibiscus (Hibiscus rosa-sinensis L.). Hortscience, 47, 1819-1820. https://doi.org/10.21273/HORTSCI.47.12.1819
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