Hibiscus plants are relatively easy to care for as long as they get their ideal environmental conditions. But what could be the reasons behind the leaves curling up or down?
Dehydration, excessive sunlight, and pest infestation are responsible for curly leaves in the hibiscus plant. Providing proper hydration, warm temperatures around 65-75°F, 6-8 hours of sunlight with some shade in summer, and daily observation are simple ways to prevent curly leaves.
There are many other reasons behind leaves curling up or down, and it is not easy to point out a single one.
You need to examine the plant closely to find out the exact problem. If your Hibiscus leaves are curling, this guide will help you know the reasons and solutions.
Why are the leaves of my Hibiscus plant curling?
There are multiple reasons for this problem.
When the plant faces something serious, the leaves tend to curl.
Their reaction to the problem they are going through and curly leaves is negative.
Some common reasons behind Hibiscus leave curling up are:
- Improper watering
- Poor quality soil
- Direct sunlight
- Temperature stress
- Nutrient deficiency or overuse
- Repotting or transplantation stress
- Pests and diseases
Let’s learn about them in detail.
Improper watering technique
Hibiscus enjoys consistently moist soil.
At the same time, the plant will not like to be overwatered.
A dehydrated plant will curl the leaves to store the moisture inside the leaves.
On the other hand, the overwatered plant will curl leaves due to root rot.
When the roots suffocate from water and are damaged due to rot, the other plant parts will fail to receive the moisture and show underwater signs.
You can identify the right problem in a few ways:
- The leaves will curl upwards during underwatering, whereas leaves will curl downwards in overwatering.
- The soil remains dry in underwatering and wet in overwatering.
- The leaves are dry and crispy in dehydration and wet and spongy during excessive moisture levels.
- If you have underwatered your plant, soak the soil properly so that the water reaches the roots of Hibiscus. Remember that the roots are 6 inches deep. So, the water has to reach that deeper.
- Don’t increase the watering amount too much. Instead, increase the frequency. Water Hibiscus 2-3 times per day until the problem is resolved.
- If you have potted plants, water thoroughly until the excess water drains out from the drainage holes. Or, take the pot and submerge it in a container filled with water for 20 minutes to give the soil a proper soak.
- If you have overwatered your plant, pause watering for 1-2 weeks until the soil has dried completely. Check it by poking your finger in the soil or using a moisture meter.
- Once the water has dried, reduce the watering amount and water it only when the top 1-2 inches are dry.
- If the plant starts root rot, you need to take the plant out, remove the roots and spray some fungicide. Find a dry location and plant it there if it is in the ground. For potted plants, use a new container and new soil.
Also read: How To Water Hibiscus Plant? (How Much, How Often & More)
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Poor quality soil
Poor drainage and retention will have the same effect as overwatering and underwatering.
Besides, improper soil pH levels will also cause curly leaves.
Hibiscus grows best when the soil pH ranges between 6.5 and 6.8.
A lower pH level increases the acidity level of the soil.
It makes toxic minerals like aluminum and manganese more soluble.
It will make the leaves curl.
On the contrary, higher pH levels turn the soil alkaline.
An alkaline soil makes necessary nutrients like iron and phosphorus unavailable.
It causes nutrient deficiency, for which the leaves lose their rigidity and begin to curl.
- If you are planting Hibiscus in the ground, consider checking the pH level with a pH tester beforehand.
- Check the soil and replant it in a new location with the ideal pH level if you haven’t checked before.
- If the result is higher than 7.5, add sulfur, iron sulfate, manganese sulfate, or aluminum sulfate to lower the pH level.
- If the result is less than 5.5, add agricultural lime or dolomite to increase it.
- Wait for 2 weeks and again test the soil to check whether the soil is suitable for Hibiscus or not.
Also read: What Kind Of Soil Does A Hibiscus Plant Like? (+Best Soil Mix)
Direct and intense sunlight
Hibiscus plants are sun-loving plants, and they need 6 to 8 hours of direct sunlight for healthy growth.
But, the direct sunlight of the summer is intolerable even to these sun-loving plants.
The sunlight intensity and the heat are so high that the Hibiscus leaves will get sunburn.
Before sunburn, the leaves will curl inwards in a cup shape to protect themselves from the direct sunlight.
If you don’t address the issue quickly, the leaves will turn yellow with white spots on the surface.
- You need to shift the plant to a shady place. It is easier for potted plants.
- If you have grounded plants, fix shading nets partially to filter the sunlight. Don’t filter the sunlight completely because that will block the PAR light.
- While planting, check whether the planting site has some trees at a distance so that they can give the plant some shade, especially in the summer afternoon.
- Increase the watering frequency to cool down the plant. Shower the plant weekly.
Also read: How Much Light Does A Hibiscus Plant Need? (What Kind, How Much & More)
Hibiscus enjoys a temperature ranging between 65 and 75°F.
They can tolerate low temperatures up to 55°F and higher temperatures up to 95°F.
Tropical Hibiscus plants are frost-tender plants and will curl their leaves to protect themselves from cold when the temperature drops below 55°F.
Sometimes, they will drop some leaves.
Similarly, the leaves will also curl up when the temperature exceeds 95 to 100°F.
The high temperature will stress the leaves for which they curl up to rescue themselves from the hot temperature.
Besides, high temperatures can increase the transpiration rate.
Due to the increase in transpiration rate, the leaves release moisture faster than their normal rate.
Over-transpiration causes withered, wilted, and curly leaves.
- You should protect your Hibiscus plant by mulching and covering it with a frost cloth. If your region receives frost, take your Tropical Hibiscus plant indoors in the fall. Maintain an ideal temperature and humidity level.
- As for the Hardy Hibiscus, you can keep them outside. Mulch them with a thick layer and cover them with frost cloth.
- Reduce the watering frequency of the Hibiscus plants. Let the soil dry and water them when the top 1-2 inches have dried.
- Cover them partially with a shading cloth and shower the plant weekly to keep them cool at higher temperatures. To avoid overheating the roots, double-pot up your potted plants.
- Mist the plant regularly to keep the leaves cool and take down the stress.
Also read: Hibiscus Temperature Tolerance: Ideal Range+USDA Zones
Without the supply of enough nutrients, Hibiscus plants will not be able to grow at their proper pace or potential.
The leaves will begin to curl and wither, the flower buds will fall off, and the plant will stunt and not have any flowers.
For optimal growth, Hibiscus requires nitrogen, phosphorus, potassium, calcium, iron, sulfur, magnesium, etc.
Due to the deficit, the plant will have stunted growth, and the leaves will lose their rigidity and curl.
However, Hibiscus won’t be able to process high phosphorus content.
Overdose of this nutrient can restrict the plant from absorbing the other minerals, thus causing nutrient deficiency and curly leaves.
Remember not to over-feed your Hibiscus plant.
That causes root burns, leaf burns, and salt accumulation.
The salts absorb all the moisture and make the leaves curl due to lack of hydration.
Overuse of slow-release will also lead to over-fertilization.
- Use a fertilizer with medium nitrogen, low phosphorus, high potassium, and other minor nutrients like iron, magnesium, calcium, sulfur, copper, etc.
- A fertilizer with an NPK value of 6-4-6 or 17-5-24 is good for Hibiscus. If you use slow-release fertilizers, use them every 3 to 6 weeks throughout the growing months and avoid using them during winters.
- Liquid fertilizers are best because they can be diluted, and there is less chance of overdose. It gives the plant adequate nutrients in time. Apply liquid fertilizers every 2 weeks in the growing season and every 4 weeks in the winter.
- Organic fertilizers are the best option to avoid over-fertilization. Some good organic fertilizers are banana peels, eggshells, Epsom salt, coffee grounds, dirty water from the aquarium, etc.
- Iron deficiency sometimes causes curly leaves, and it can be addressed if you apply iron chelates. But, you should check the fertilizer you are using. This iron supplement will not solve phosphorus overdose if it has high phosphorus.
- Don’t apply fertilizer in chloride form. You will have to apply it with every feed, and that can result in chlorine overdose.
Also read: What Is A Good Fertilizer For Hibiscus Plants? (Ideal Ratio+Best Pick)
Hibiscus plants are fast-growing plants and can reach around 10-15 feet within a few years.
If you grow them in containers, you need to repot them every 1-2 years.
While repotting, the plant will go through a change.
Getting dug up and moved from one place to another in new soil will shock the plant.
Transplant shock will also happen if you don’t repot the plant properly.
This shock will stress the plant.
It will react negatively by having yellow leaves, curled leaves, wilted leaves, and some defoliation.
But, once the plant gets habituated to the new environment, it will stop showing these signs of stress.
- Generally, there is no particular solution because this kind of shock is natural. Try to maintain the same growing conditions for your plant as before. The light, water, and soil requirements should be the same.
- While repotting, be careful and follow all the steps properly without fail. Don’t wound the good parts of the plant, and don’t fertilize it for 2-3 months.
- Other circumstances could be exposing the roots to open air for too long or repotting at the wrong time. Always transplant Hibiscus in spring and summer. Don’t let the roots stay in the open air for a long time. It can dry out the roots.
Bugs are a major threat to all the plants, including Hibiscus.
They suck the saps of the leaves and make them curl and wither.
Various sap-sucking bugs attack the Hibiscus plant.
Aphids: These sap-sucking insects suck out all the saps and nutrients from the plant and make the leaves yellow and curly.
They are hard to detect until their community becomes more prominent.
Spider mites are tiny black or red-colored bugs detected only when they leave behind white webs.
The leaves will have yellow dots all over.
Over time, the leaves will become yellow, dry, and curly.
Japanese beetles: The larvae of these beetles feed on the plant’s roots. The larvae stay in the soil and feed on the roots.
Due to this destruction, the roots will fail to transfer the moisture and nutrients to the leaves, making them yellow, curly, and withered.
Many pests like scales, whiteflies, mealybugs, worms, caterpillars, etc., will destroy the plant and result in curly leaves, yellow leaves, skeletonized leaves, etc.
While inspecting pest infestation, consider checking the underside of the leaves.
It is the home of most pests.
There are lots of products available in the market for eliminating pests.
But be careful while choosing one for your Hibiscus.
While using chemical products, please read the instructions on the label and then use them.
- Natural methods include showering the plant forcefully and rubbing them off the plant. You can also release natural predators like lacewings, ladybugs, and mantis to the garden bed.
- Use Neem oil. Add 1/3rd neem oil with 2/3rd water and spray the mixture to the infected parts of the plant. You can normally mist the plant with neem oil once a month to prevent further infestation.
- Damp a cotton ball with rubbing alcohol and dab it on the infected area. It will weaken the hard-shelled pests and also kill them.
- Use insecticidal soaps to coat the bugs. The soap will cut off the oxygen and kill the bugs.
- Use Imidacloprid in the soil and let the plant absorb it. When the pests suck the saps, they will also absorb this chemical and get killed.
Also read: How Do I Get Rid Of Bugs On My Hibiscus? (Common Bugs+Fix)
Diseases make the plant weak, and the leaves curl.
Leaf spot: Brown with yellow haloes all over the leaf surface is a sign of a fungal disease.
It will cause yellow leaves and black spots.
The disease decreases the plant’s ability to perform proper photosynthesis and eventually makes the leaves curl to save energy.
Root rot: The disease is the result of prolonged overwatering.
The roots will rot and fail to hold the moisture and nutrients.
Due to this, the leaves will not receive the moisture they need and become curly drooping and yellow.
Wilt or dieback disease: In these two diseases, generally, all the leaves or the leaves of one particular branch will wilt.
It is an indication that the plant is infected.
When they are sick, they fail to absorb any water and nutrients and begin to curl and droop.
If left in such a condition, the plant will be more unwell over time.
- First, you need to isolate the plant, remove the affected parts and discard them to avoid spreading. While removing the damaged parts, disinfect the gardening tools before and after use.
- Apply some fungicide to the infected areas to kill the fungus. If you could apply Neem oil the moment you spot the fungal disease, it would help to prevent the disease from spreading.
- Keep the surroundings clean. Remove the fallen leaves and other debris.
- In the case of root rot, take the plant out, remove the infected roots, apply some fungicide and plant it in a new location.
- If you use a container, use new soil and container to plant them. Water the plant only when the top 1-2 inches of the soil is dry. Don’t fertilize until recovery.
- Transplant the plant to some other safe location.
Prevention is better than cure. You can prevent curling by maintaining the right conditions for your Hibiscus plant.
- Find the right spot for planting Hibiscus plants, a location that receives 6 to 8 hours of sunlight. Some trees around would be fine, giving them shade in the afternoon and reducing sunburn risk.
- Use a good soil mix with well-drained loamy soil like composted bark, perlite, coco coir, and peat moss. The soil needs to be porous for the roots to hold oxygen.
- If you are planting in the ground, check the water permeability and pH level (6.5-6.8).
- Choose the right size of a container if you are using one.
- Water the plant carefully. Don’t dump a lot of water into the soil or use too much. Water the Hibiscus only when the top 1-2 inches are dry. Hibiscus needs more water in the summers and less in winters.
Curly leaves signify stress, and you need to find and fix the reason behind the problem to bring back the plant. As long as you follow the growing conditions, your plant will grow seamlessly without issues.
Reference: Wikipedia, ASPCA, Louisiana State University Agricultural Center, American Society for Horticultural Science, Tropical Hibiscus by Texas A&M University, Sciencedirect.