Is your favorite hibiscus plants not flowering this year with the usual abundant flower display, and you’re not sure why?
This has happened to me too! I had been diligent about my hibiscus plant care all year, and it did not reward me with the beautiful flower display that I had come to expect from it! Oh, my dismay! What had gone wrong? I didn’t want to face another year without my hibiscus flowering.
Fortunately, I actually work at a garden center, so I was able to ask some of the expert hibiscus growers that supply our garden center firsthand for a reason for my lack of hibiscus blooms. We went through all the potential causes, and we finally identified the culprit.
I had pruned my hibiscus at the wrong time of year! I pruned it at the same time as my roses in late Winter/ early Spring. While pruning at this time works for roses, it prevented my hibiscus from flowering.
Other potential reasons why your Hibiscus is not flowering are that it is in too much shade, stressed due to drought, or too much Nitrogen fertilizer has been applied, which promotes hibiscus foliage growth with fewer flowers.
From my research, there is also a problem very specific to hibiscus, which is that too much phosphorus also prevents flowering.
But fear not, my friends! In this post, I’ll share with you all the tips and secrets I’ve learned to identify why your hibiscus is not flowering and the solution to solve it so that your hibiscus flowers the following year.
Hibiscus flower in the Summer months. If your hibiscus has not flowered, then keep reading to learn why and how to promote flowers on your hibiscus…
1. Not Enough Light? Too Much Shade Prevents Your Hibiscus Flowering
From my research, I’ve learned that the most important condition for hibiscus to flower is the amount of sun it receives per day.
So, if your hibiscus is in a shadier location in your garden, then it will have less energy to display flowers in Summer.
For us to get your hibiscus flowering as best as we can I think its helpful if we appreciate where they grow in the wild…Hibiscus are indigenous to the sunny and humid tropical and subtropical climates in Asia where they flower in full sun and warm weather.
Therefore I advise you to always locate your hibiscus in an area with 6 or more hours of sun whether they are a variety of the tropical species of hibiscus (Hibiscus rosa-sinensis) or the hardier species of hibiscus (Hibiscus spp.) as both require full sun for flowering (hardier hibiscus can tolerate cooler temperatures).
So, if your hibiscus is in a shady area of your garden or indoors, then the plant is living in conditions that are contrary to its requirements, and I can tell you it is this that causes stress and prevents flowering.
So what can we do? If possible, I would cut back any vegetation that is casting shade on your hibiscus, or ideally, if it’s potted, move it to a sunny patio. You can also transplant your hibiscus to a sunnier part of the garden (from experience, this is best done in the Spring).
Only the tropical varieties can grow indoors (hibiscus are not necessarily the best houseplants) but ensure that your hibiscus is in the sunniest window of your house to promote blooms.
2. Too Much Phosphorous can Prevent Hibiscus Blooming
Whilst phosphorous is often the key ingredient for ‘bloom boosters’ in fertilizers, I learned that they are to the detriment of hibiscus flowering as hibiscus is particularly sensitive to a build of phosphorous in the soil!
But why is this?
An accumulation of phosphorous in the soil prevents the hibiscus roots from drawing up other essential nutrients, which can stop your hibiscus from flowering and even cause the plant to die.
So I would avoid any fertilizer that is not well balanced (a well-balanced fertilizer has an even ratio of Nitrogen, Phosphorous, and Potassium NPK) and avoid any heavy use of fertilizer, prioritizing improving soil fertility with organic mulches (such as well-rotted manure).
Hibiscus is unusual in its sensitivity to phosphorous so I have found this can be a frequent cause of the flowers not emerging for gardeners as it is quite a specific problem.
(Too much phosphorous is one of the causes of hibiscus leaves turning yellow however there are several reasons why hibiscus leaves turn yellow so I wrote another article for the solution).
3. All Foliage and No Flowers? Too Much Fertilizer Prevents Your Hibiscus Blooming!
As we discussed, our hibiscus is sensitive to too much phosphorous and even nitrogen when you use fertilizer in a concentration that is too high. A lot of people I’ve spoken to have this problem because they are killing their hibiscus with kindness!
So, we need to acknowledge that too much nitrogen causes your hibiscus to grow foliage at the expense of blooms so it’s important to moderate your applications.
I have also personally observed that too much fertilizer can also increase the hibiscus’s vulnerability to pests such as aphids which feed and sap and can cause flower buds to drop so if it’s infested.
The expert growers taught me that hibiscus is a heavy feeder, but as stated, the best way to feed them is to add mulch to improve the soil (garden compost or leaf mold) and use a general fertilizer from a brand such as miracle-gro, once a month during the Spring and Summer.
I would avoid using any manure as mulch as this contains a high concentration of nitrogen, which is why I always use garden compost or leaf mold.
Important tip: I personally use the granular formulation of the fertilizer as I find it releases the nutrients slowly over the course of the season. This prevents too much nitrogen from being in the soil at the vital flowering period.
This is often a good balance to provide the hibiscus with the nutrients it requires to display flowers without overindulging the plant and causing it not to flower.
How to Solve it?
If your hibiscus has no flowers but lots of foliage, I urge you to scale back the use of fertilizer and water it regularly. Regular watering really helps, as it dilutes the concentration of fertilizer.
To be honest, when this happened to me, It took the following year before my hibiscus flowered again, so I’m afraid some deferred gratification is required.
4. Pruning at the Wrong Time of Year (Have you Pruned too Early?)
This is the one that happened to me! I was so gung-ho with the pruners when it came to sniping back my beloved roses, and I carried on this same enthusiasm when it came to my hibiscus. It was late February or early March, and I gave my hibiscus a jolly good prune as it became unruly!
What I subsequently learned is that Hibiscus flowers on new years growth so pruning in the growing season can have a serious impact on blooms.
A heavy pruning in the early Spring can either cause the hibiscus to not flower in the Summer or to delay flowering significantly. In my case, my hbisucs did not flower at all!
When I talked to experts about this, they told me that if flowering is delayed, the flowers are more likely to emerge when the temperature is cooler in the Fall rather than in the height of Summer and often wilt or drop far quicker than they otherwise would.
What I’ve learned is that a Hibiscus responds better to a light prune at the end of the growing season after flowering around September/October so new growth can in Spring can support the flowers.
5. Why is Your Potted Hibiscus Not Blooming? (My Tips for Hibiscus in Pots)
So, as I’m sure you can imagine, the same reasons for hibiscus not flowering also apply to potted hibiscus, but a few conditions specific to pots may cause your hibiscus not to flower.
If your potted hibiscus is not blooming, then here are the most common reasons that I encounter:
- Has the hibiscus has been in the same pot for many years and exhausted the available nutrients? What we have to remember is that pots have a limited capacity for soil and, therefore, fewer available nutrients. What I’ve also noticed is that potted soil can also become compacted over time, and frequent watering washes out water-soluble nutrients.
- Small pots dry out too quickly. Hibiscus requires full sun, warm temperatures, and consistently moist soil to flower. The consequence of this? Smaller pots retain less water and heat up quickly in the soil, which increases evaporation and causes drought stress to your hibiscus. Even with consistent watering, they prevent hibiscus from flowering.
- Pots without drainage holes in the base. I am seeing this more often in supermarkets and garden centers. Hibiscus requires well-draining soil, so if they are planted in decorative pots without drainage holes in the base, water pools around the roots, causing root rot, preventing flowering, and causing the plant to die back.
- In smaller pots, the roots can become pot-bound and even cause a blockage for the drainage holes of the pot, which causes slower drainage and boggy soil and increases the risk of diseases.
If your hibiscus has been growing in the same soil for many years, you should repot it to promote plant health and flowering. I know I’ve had this happen myself, as I’ve delayed repotting for a year or so!
What worked really well for me was to Re-pot it with quality multi-purpose compost for good soil structure and moisture-retaining capacity.
I chose a pot that is only 2 inches (or so) in diameter larger than the previous pot so the roots can establish and access the nutrients and moisture they require for flowering without drying too quickly in the intense Summer sun.
But why only increase the pot size by a 2 inch increment I hear you ask?! Good question! This is to avoid overpotting. This is where you repot your plant into a much larger pot then the previous pot which can actually hold moisture too long for the hibiscus to tolerate!
Pro Tip: So if you live in a hot climate like I do, then I recommend repotting your hibiscus into a plastic or ceramic pot rather than clay or terracotta. This is because clay and terracotta are porous and, from experience, can dry out too quickly for your hibiscus to tolerate. Plastic and ceramic are impermeable, which helps retain moisture. Since I’ve implemented this tip with my potted hibiscus, it has flowered much better!
Just ensure that your pot or container has drainage holes in the base and place a one-inch layer of gravel in the bottom of the pot to ensure good drainage.
(To learn how to save hibiscus, read my article, how to revive dying hibiscus).
6. Is Your Climate too Hot or Cold for your Specific Hibiscus?
As we discussed, hibiscus are native to tropical and subtropical climates in Asia, where they thrive in sunny, humid, and warm conditions.
There are two species of hibiscus grown by gardeners:
- Tropical hibiscus (Hibiscus rosa-sinensis)
- Hardy hibiscus (Hibiscus spp.)
So what’s the difference?
Tropical hibiscus requires warmer more humid conditions typically and does not tolerate freezing temperatures (hardy in USDA Zones 9-11).
The hardy species can tolerate a wider temperature range and generally flowers for longer than the tropical hibiscus, although this can depend on the specific variety. The longer flowering duration and greater resilience to temperature fluctuations are the reasons why I chose to grow the hardy varieties.
I’ve also found that tropical species are much harder to care for outside of their typical climates and, therefore, do not flower as readily as they are often stressed if conditions are not to their liking.
I actually called different garden centers all over the country in different climates, and from my informal survey, I learned that the hardy species tend to flower more readily in a greater range of climates and conditions, so I would fully encourage you to grow the hardy species!
If you’re struggling to get your hibiscus to flower, then check what species the variety belongs to and plant the appropriate hibiscus for your climate for improved flowering.
7. Lack of Hibiscus Flowers? Could Underwatering be the Reason?
As we talked about, our hibiscus plants are native to the tropics, where they grow in soil with a high organic content in areas of frequent rainfall.
If your hibiscus is not flowering then this can be because it is stressed due to drought.
Let’s keep in mind that Drought stress is typically caused by 2 things:
- Under watering. Whilst established hibiscus may not require as much regular watering, potted and less mature hibiscus shrubs should be watered as frequently as required so that the soil is consistently moist to promote plant health and flowering in the Summer.
- Sandy soil does not retain enough moisture. If your soil has lots of sand or stone then typically it drains too fast for the roots of your hibiscus to draw up moisture which causes drought stress and can reduce flowering.
To improve your soil’s capacity for retaining moisture, I recommend giving your hibiscus a good soak with a hose and then applying a layer of mulch to the surface of the soil around your hibiscus.
Materials such as compost, leaf mold and straw are excellent mulches for hibiscus as they retain moisture, add nutrients and maintain the soils pH to suit your hibiscus.
The mulch also improves the soil structure, so apply a layer around your hibiscus plants at the start of Spring. I love to do this before the weather heats up, as when the sunshine hits, it is not directly on the ground drying out the soil around your hibiscus roots but rather on the layer of mulch. This step keeps your hibiscus roots cool.
The frequency of watering depends on your climate and the weather but if you test your soil for moisture to a finger depth regularly you can determine how quickly your soil dries out.
If your planting hibiscus in pots and the soil dries out too quickly I recommend reporting to a larger pot and using a ceramic pot to help retain moisture! I personally water my potted hibiscus when the top inch of the soil feels dry and my hibiscus flower every year.
As soon as the soil is dry, give your hibiscus a good soak to ensure a healthy plant that displays flowers in Summer.
8. Poor Drainage in Your Garden? Hibiscus Does Not Flower in Slow Draining Soils
On the other end of the spectrum is hibiscus not flowering if the ground is boggy. Whilst hibiscus requires consistently moist soil it should also be well-draining. (You gotta find that happy medium!)
If your soil is heavy clay or compacted and water pools around the roots of the hibiscus it can suffer from stress that causes it not to flower and promote the conditions for fungal disease such as root rot which can cause your hibiscus to die back.
In my experience, Hibiscus is one of those plants that often does not last long in saturated soils such as heavy clay so I recommend that you should transplant it to an area of well-draining soil or into a pot if it is small enough.
For boggy, low-lying gardens, I recommend growing your hibiscus in pots, containers, or raised beds. These have more favorable drainage conditions, and you can customize the soil profile so that it is suitable for hibiscus growth and flowering. I can tell you from my years as a landscape gardener that this is far easier than amending boggy garden soil!
In my experience, you have to recreate the conditions of a plants native environment to keep it happy, and if you have a boggy garden then I would simply plant hibiscus in pots if you want them to flower.
9. Blooming Battle Ground! How Pests Can Cause Hibiscus Your Flower Buds To Fall Off
This is the least common reason that I have personally encountered for hibiscus, but we’ll still talk about it as I have seen it come up once or twice.
Our hibiscus is usually quite resilient to pests and diseases, but if the hibiscus is under stress for any reason, then this can increase the risk of infestations that cause hibiscus flower buds to drop or not open properly.
These causes of stress are:
- Water stress due to drought or boggy soil.
- Too much fertilizer.
- Nutrient-poor soil.
This is the most likely scenario as, like I said, people often kill their plants with kindness! Too much nitrogen from fertilizer, in particular, causes more soft and succulent foliage growth, which attracts insects such as mealy bugs, aphids, thrips, and spider mites.
I once saw this happen when someone applied lawn fertilizer to their lawn, and it then rained heavily, diluted the fertilizer, and washed the nitrogen into their flower bed, which caused a nitrogen overload for the plants, which caused the hibiscus to turn droopy and vulnerable to pests.
Inspect the leaves and if you notice any sign of insect pest infestations then use an organic insecticide derived from neem oil (available from garden centers and on Amazon) as neem oil is not toxic to other animals in your garden and can sort out your insect problem.
From experience, the spray typically takes 2 or 3 applications to the leaves to sort out an infestation. Your hibiscus may not recover in time to flower this year, but getting rid of pests keeps your hibiscus healthy, and it should flower the following year.
Do you have any more questions or insights about hibiscus flowering? Please leave a comment below! I’d love to hear from you!
Key Takeaways:
- The reason for hibiscus not flowering is usually because of too much shade, drought stress, or too much fertilizer. Nitrogen promotes foliage at the expense of flowers, and too much phosphorous reduces hibiscus blooms by immobilizing nutrients in the soil.
- Pruning at the wrong time can prevent flowering as hibiscus flowers on new growth. Avoid pruning in the Spring or Summer. The best time to prune hibiscus for flowering is in the Fall.
- Drought stress or slowing draining soils can prevent hibiscus flowering. Hibiscus requires consistently moist, well-draining soil to display flowers without stress. Unhealthy plants are less resilient and more likely to be affected by pests or diseases.