Hibiscus produces gorgeous bright blooms with supersized flowerheads. The shiny green leaves add to their appeal.
Yellow leaves on hibiscus don’t look pretty, but they don’t mean your plant is sick. It does mean that something is stressing it.
When hibiscus plants are stressed, they show their displeasure by losing their greenery. Yellow leaves are a sign of stress.
Destress your plant, restore the greenery.
The key to doing that is figuring out what’s stressing your hibiscus.
Why are my Hibiscus Leaves Turning Yellow?
Hibiscus leaves turn yellow when they’re stressed. That happens when they receive too little or too much water, which can be affected by slow-draining soil. Other stress factors include insufficient sunlight or overexposure, as well as sap-sucking insects that can dehydrate the plant making it appear like it’s underwatered. Until you find and fix the issue stressing the plant, leaves will continue to yellow and eventually drop. Yellow leaves won’t recover but once you find and fix the stress factor, you can prune off discolored leaves to allow new healthy foliage to emerge.
5 Stress Factors That Contribute to Yellowing Leaves on Hibiscus
Getting the Watering Levels All Wrong
Hibiscus plants can get very thirsty, especially the tropical varieties.
In the summer, they need watering daily, possibly twice a day when temperatures soar over 80oF.
If they don’t get their liquid top-ups, the leaves will yellow.
But the same will happen if you keep that frequent watering up in the winter when the plant goes into dormancy.
Overwatering and underwatering will cause the leaves on the hibiscus to turn yellow.
The only way to avoid it is to water when needed. Soil moisture is your best indicator of when to water.
During the summer, add enough water to keep the soil moist but never as much that causes soggy soil.
Soggy soil is worse than dry soil because that will drown the roots and kill the plant. At least if it’s underwatered, you can give it a drink to perk up its lush leaves
In the winter months, you’re only watering to keep the soil from drying out.
The plant won’t be actively drinking much of what you put in the soil when it’s dormant, so you only really need to be replenishing water lost to evaporation.
Using Soil that Doesn’t Drain Fast Enough
Closely related to watering issues is soil drainage.
Potted hibiscus will need to have containers that feature lots of drainage holes to prevent overwatering.
The most suitable soil types with adequate drainage are loam and sandy loam. Clay soil will need to be amended as it holds water for longer.
The slower your soil drains, the more likely it is for the leaves on the hibiscus to yellow. It’s the same symptom of overwatering because that is the result.
The roots of the hibiscus plant do not like to sit in standing water. Well-draining soil prevents that.
Complicated Relationship with Sunlight and Shade
The more leaves a hibiscus has, the more sunlight it needs to support each of them. The most shaded leaves are the ones most likely to yellow.
If your leaves are crowded, the lack of sunlight reaching some leaves could be all that needs to be fixed.
Use selective pruning to open it up, letting more light reach the leaves.
You need to strike a balance though because the shade can be good for hibiscus.
Too much sunlight, which is over 6 hours of direct sunlight, will burn them.
Hibiscus leaves suffering from sunburn have yellow leaves with white spots.
Yellow leaves without the spots are a result of too little sunlight.
Temperature Variations
Leaves turn yellow when the plant is thirsty. Hot weather will cause that if you don’t increase the water supply.
Hibiscus plants thrive when temperatures are maintained at 65°F to 85°F (18°C to 29°C).
Above or below that will stress them. Since stress causes leaves to yellow, you need to address the temperature issues.
During intense heatwaves, watering more frequently could be all that’s needed to fix yellowing leaves.
But, if your soil can’t drain fast enough to cope with the increased watering, an alternative is to shade your plant.
If you decide shading your plant is the way to go, consider growing a tall plant to benefit from dappled sunlight.
It’s better than indirect sunlight because it has more PAR (Photosynthetically Active Radiation) that the hibiscus needs for blooming. Without sufficient PAR, hibiscus produces lush green leaves but struggles to bloom.
If it’s cold stress that’s causing the yellowing of the leaves, applying a layer of mulch over the topsoil and sheltering the leaves from wind may be required.
Related to consistent temperatures are sheltering hibiscus from the wind.
To outdoor plants, the wind has the same effects as drafts do on indoor plants. It causes temperature reductions in parts of the plant.
If you’re noticing yellowing leaves on only one side of the plant, consider if it has sufficient shelter from the wind. It might just be too drafty.
Insects
Spider mites, thrips, aphids, Japanese Beetles, whiteflies, and mealybugs are all sap-sucking insects that can make your plant act like it’s underwatered.
Additional damage will be evident though. Insects tend to hide out on the underside of leaves.
If you think you have your growing conditions in check for your hibiscus to thrive, inspect the leaves for insects.
Treating a pest infestation is the only way to help your hibiscus heal.
Frequently Asked Questions about Hibiscus Yellow Leaves
Should I remove all the yellow leaves?
Once leaves turn yellow, they won’t magically go green again. They will drop. Leaf drop is what follows yellowing. You may as well pinch them off before they drop. They grow back fast anyway.
How long does the hibiscus take to recover from shock?
Hibiscus are resilient, but sudden changes can shock them, such as taking a newly bought nursery-grown hibiscus and transplanting it in garden soil. In the first few weeks, the sudden change will be stressful. Some leaves will yellow, and partial leaf loss inevitable. Keep your plant maintenance consistent and after a few weeks, or at least within the first month, hibiscus will acclimatize to the new growing conditions.