Hibiscus plants have become widely popular due to their colorful flowers. Besides, they are also beneficial for health. But, certain unfavorable conditions can stress them out and cause white leaves.
The primary causes behind white Hibiscus leaves are powdery mildew, high-intensity sun, and pest infestation. Make sure the plant is not exposed to excessive direct sunlight. Ensure air circulation with high humidity and use neem oil to prevent the infestations from spreading.
If you notice white leaves on your Hibiscus, read this article till the end. In this guide, I will share the problems and the solutions. With adequate supervision and guidance, your Hibiscus will bounce back to greenery within a few weeks.
Why do Hibiscus leaves turn white?
There are not many reasons behind the problem.
So, your plant will not die if they are turning white.
With quick action and the right steps, the leaves will stop turning white, and your plant will develop new leaves after recovery.
The problems behind white leaves in the Hibiscus plant are:
- Excessive sunlight exposure
- Powdery mildew
- Pest infestation
Let’s learn how these situations make the leaves white and what possible treatments can remove them.
Excessive exposure to sunlight
The Hibiscus leaves can turn white due to sunscald or sunburn.
Though Hibiscus plants are sun-loving plants, they too will get sunburnt when exposed to high-intensity sunlight.
When the Hibiscus plant receives excessive sunlight, the chlorophyll will experience damage due to the heat.
Eventually, the affected leaves turn white in certain places over the leaf surface.
It is mainly seen in the summer when the sun’s heat is too high.
The heat intensity is so heightened that it scorches the leaves badly.
The leaves will have a bleached look which is quite unattractive.
Sunburn in the Hibiscus plant occurs during two situations:
- When your plant gets harsh sunlight for more than 8 hours, especially during the summer.
- When you shift your indoor Hibiscus plant outdoors without acclimatizing it.
If you have spotted it in one particular plant, fixing and preventing it now is the right time to keep all your Hibiscus plants safe and happy.
How to fix sunburn?
The leaves scorched by the high-intensity sunlight will automatically fall off the plant.
They won’t turn back green.
But, if you don’t like its sight, you can prune them.
To save the plant from getting any further sunburn, shift the plant to a partially shady place.
It is easy for potted plants.
If your plant is in the ground, fix shading nets in the afternoon as it is the time when the sun gets too harsh.
How to prevent it?
Suppose you have bought a new Hibiscus plant home.
It is better to keep it inside in a comfortable and controlled environment for some days.
When you think of shifting the plant outside, be gradual.
Start exposing them to filtered light, partial light, and direct sun. Follow this order.
While exposing the plant to direct sun, it should be only 2-3 hours.
Then again, please bring it back to the shade.
Slowly increase the timing every week.
Being gradual will help the plant adapt to the new light conditions.
After some days or weeks, you can keep your plant under the direct sun without any issues.
Give your plant a break from the harsh sunlight, especially during the summer afternoons.
It will let your plant adjust to it without stress.
While planting Hibiscus in the ground, find a location receiving 6 to 8 hours of sunlight, with some shade in the afternoon.
It would help if some tall trees were around to guard the sunlight slightly.
It will give the plant some dappled shade and reduce sunburn risk.
Instead of finding trees, you can partially fix shading nets, especially during summer afternoons.
Don’t fully shade the plant.
Natural light is required to let the plant have some PAR for photosynthesis.
If your plant is in the container, don’t change it while transitioning.
Even if the light condition changes, the plant will receive a familiar growing condition from the container.
Also read: How Much Light Does A Hibiscus Plant Need? (What Kind, How Much & More)
If you find white spots on the leaf surface as if someone has spread some talcum powder over it, it is an evident sign of powdery mildew.
This white color will become grey or brown when it begins to cover some more areas of the leaves.
Powdery mildew is common when the plant is around highly humid areas with damp conditions.
You need to stop this fungus disease before it gets the chance to cover more parts of the plant.
Otherwise, it won’t be easy to fix.
Reasons behind powdery mildew
There are a few reasons behind the fungus development.
- Overwatering: Hibiscus needs regular watering, but the topsoil has to remain dry for 1-2 inches. Not letting the soil dry before watering or dumping lots of water at once can increase the moisture level and cause overwatering.
- Poor drainage: Hibiscus likes to remain moist, but the soil should still be well-drained. If not, the moisture will keep the soil damp for a long time.
- High humidity levels without airflow: Hibiscus likes high humidity to thrive. But you must make sure that the plant receives enough airflow to help the soil dry out. Otherwise, it will result in prolonged wetness. Your plant will end up having powdery mildew.
- Infection from other plants or objects: Sometimes, the plant will have this infection despite you taking proper care of it. It got transferred from another affected plant through gardening tools or other plants if they were too close.
How do I treat powdery mildew?
Prune the affected leaves from the plant to stop the disease from spreading.
Use sharp scissors or pruners, disinfect it with sanitizer or rubbing alcohol and prune the infected leaves.
After pruning, wash the pruners.
Otherwise, other plants can get infected when you use this pruner.
If lots of leaves got affected, cut off only the maximum affected leaves.
Removing too many leaves can shock the plant and make it weak.
Use Neem oil.
It is a wonderful antifungal agent that works perfectly to remove fungal diseases. Pour it into a cotton pad and use it on the infected leaves. You will notice signs of improvement within a few weeks.
For using it as a spray, mix 2 tablespoons of neem oil solution with one gallon of water.
Spray the leaves with it every week until you notice any signs of progress.
While using neem oil, the plant shouldn’t get exposed to the sunlight.
So, do it in the evening.
One easy homemade treatment is by using baking soda.
It works great as a fungicide – mix one teaspoon of baking soda, a quarter of water, and some vegetable oil.
Shake the mixture well in a spray bottle and apply it to the infected leaves.
You can also use one teaspoon of the soda, 1-gallon of water, and one tablespoon of dish wash soap.
Use it every alternate day until you can see any progress.
Another homemade treatment is with milk powder.
Add one part of milk powder with 3 parts of water.
Mix the solution well and apply it to the infected parts.
Though it will take several weeks, it will show some positive results in your plant.
If the above methods fail, you need to use commercial fungicide sprays.
It should be used as a last resort.
First, try the above approaches.
Observing the plant can help you catch the problem at an initial stage.
Then, the above methods can help reduce the problem.
How to prevent powdery mildew?
- Water the plant base below the leaves to keep the plant healthy. Avoid splashing water on the leaves regularly as that creates a high humid level, thus increasing the chances of mildew.
- Always water the Hibiscus plants in the early morning. If the summer is too scorching, then perform second watering. But the main watering has to be done in the morning.
- Avoid using high nitrogen content fertilizers.
- Let Hibiscus have enough air circulation. If you wish to keep any other plant close to Hibiscus, keep at least 2-4 inches of space. Maintaining proper airflow with correct humidity will stop the fungus from developing.
- The moment you notice white spots, observe their motion and treat them quickly if it is mildew. It will stop the disease from spreading.
Also read: How Do I Get Rid Of Bugs On My Hibiscus? (Common Bugs+Fix)
Three pests whose infestations can create white marks on the leaves or make them whitish are mealybugs, whiteflies, and snow scales.
Mealybugs attack Hibiscus plants when they are in damp conditions for a long time.
They stay under the leaves and suck the sap of the leaves.
The leaves and the stems will have the white stuff, which is soft and cottony-type.
The leaves look whitish due to these white substances.
Mealybugs secrete honeydew after feeding on the plant sap.
This white stuff will feel sticky due to the secretion of honeydew.
They are white and have four wings, but these are not general flies.
Sometimes, if you find your leaves have white spots or patches on the surface, they are these whiteflies.
They, too, suck the plant sap and release honeydew.
When you shake the plant, they will all fly off for some time.
Again after some hours, they will come back to feed.
Both these bugs suck the plant sap containing the essential water and nutrients.
It can turn the leaves slightly whitish-yellow at the beginning of the infestation and then full yellow.
Sometimes the Hibiscus plants and trees will have white specks on the branches and trunks.
These are due to an infection caused by snow scales.
They remain attached to the branches and feed on the plant’s nutrients.
How do I get rid of the pests from the plant?
- You can remove the sap-sucking bugs systemically by applying Imidacloprid. The plant will absorb this chemical. When the bugs again suck the sap, they’ll consume this chemical and die.
- Shower the plant thoroughly to dislodge them and fly them away.
- Neem oil is also helpful. Spray some neem oil to the infected parts of the plant. Remember to apply this in the evening because a plant sprayed with neem oil and exposed to the direct sun can burn the leaves.
- Use natural predators to control the infestation. Release ladybugs, mantis, and lacewings.
- For bugs like snow scales and mealybugs, use rubbing alcohol to weaken their shield. Please don’t use water-based pesticides because they won’t work over these bugs. They have a protective shell that protects them from these pesticides.
- You can use sticky cards for the whiteflies. When they fly, they will get stuck in the card and won’t be able to free themselves from it.
- For removing the hard-shelled snow scales, mix equal parts of baby oil and rubbing alcohol. Mix and brush the solution directly over the bugs. It will weaken their shell and kill them. After 30 minutes, wash the plant to remove the corpses.
- Use insecticidal soaps or soapy water. Add one tablespoon of liquid soap with one gallon of water. Mix it well and apply it to the leaves, stems, and wherever you find the bugs. Apply it every few days.
- If the above method fails, use chemical insecticides and pesticides to get rid of bugs. Use it as a last alternative.
- It would be best if the plant didn’t receive direct sunlight during these treatments.
Tips to keep Hibiscus plant healthy
- Let Hibiscus have 6 to 8 hours of sunlight. But also save them from the extreme heat of the sun.
- Water the Hibiscus regularly, but only when the top 1-2 inches are dry.
- Use well-drained loamy soil to prevent frequent droughts and overwatering.
- Feed Hibiscus every 2 weeks with a water-soluble fertilizer with proper NPK value, 17-5-24. You can also use Earthpod Hibiscus and Tropical Flower Formula.
- Maintain temperatures between 65 and 75°F.
- Maintain 50% to 70% of humidity level.
- Also, ensure good air circulation.
- Observe your plant daily to watch for pests and diseases and take immediate steps if you notice any symptoms.
- Mist your plant with neem oil every 15 days or once a month. It will keep the infestations at bay, the plant healthy, and cure infections if there are any.
Hibiscus leaves turning white or having white spots doesn’t mean the plant will die. The problem can be as serious as powdery mildew or less harmful and common as sunburn.
Before you declare anything, identify the problem and cure it as soon as possible. Even if the problem appears to be less harmful, you shouldn’t ignore it. Follow the care tips I shared to avoid problems.
Reference: Wikipedia, ASPCA, Louisiana State University Agricultural Center, American Society for Horticultural Science, Tropical Hibiscus by Texas A&M University, Sciencedirect.