Hardy hibiscus plants are a landscaping staple, brightening up gardens with their giant blooms. But as with many plants, there are certain conditions you need to help your hibiscus plant thrive. Learn why your hibiscus leaves are turning yellow—and how to turn the situation around.
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Common Causes of Yellow Hibiscus Leaves
Before you start playing plant detective, understand that having some yellowing hibiscus leaves—especially on old growth—is totally normal. "Before the older leaves fall, the plant sends a ‘retirement signal’ to the leaf and the plant stops the production of chlorophyll in that leaf, pulling any remaining collected energy back into the plant," says Jennifer Foster, plant expert at Fast Growing Trees.
But if you're getting a lot of yellowing on new growth, there may be an underlying issue you need to fix.
Why Your Plant Leaves Are Turning Yellow—and How You Can Fix It
Over- or under-watering your hibiscus plant
Too much or too little water is the most common reason why your hibiscus leaves may be turning yellow. "If the soil is staying soggy, then this can cause the roots to rot," says Cate Singleton, director of design at online landscape design company Tilly. "But hibiscus plants need a good deal of water. If the soil gets too dry, this can cause stress to the plant."
Changes to the plant's environment
Any changes to your hibiscus plant's environment—such as more shade, less humidity, or cooling temperatures—could cause the plant's leaves to yellow. "It can cause the plant to drop some leaves in order to adjust to the new environment," Foster says.
Lack of sunlight
In most parts of the country, hibiscus plants require full sun to thrive—so if your plant isn't getting that, it may drop some leaves, Singleton says.
Nutrient deficiencies
Haven't fertilized your hibiscus plants in a while? A lack of nutrients—particularly phosphorus and nitrogen—can be to blame, Foster says.
Insect infestation
Pests like spider mites, aphids, and mealybugs can all be potential culprits if your hibiscus has yellowing leaves. "Their feeding habits can cause yellowing of leaves," Foster says. "Check the undersides of leaves as well as the spaces where leaves and branches intersect, all of which are good places for insects to hide."
Note that an insect infestation could be a sign that your plant is weakened by another issue, such as incorrect watering or nutrient deficiencies. If so, addressing that other issue can help
How to Solve Yellowing Hibiscus Leaves
Fortunately, for every problem, there's a solution that helps stop the yellowing of leaves. Try these tactics to help your hibiscus plant thrive.
Water your hibiscus plant properly
Your hibiscus should be in well-draining soil, and get water every few days for optimal growth. If your plant is soggy, try adding compost to the soil to correct it, while mulching the plant (and of course, watering more) can help if a lack of water is to blame, Singleton says.
Help your plant get an appropriate environment
"If you will be moving the plants between indoor and outdoor locations, make sure you acclimate the plant slowly between each location to reduce stress on the plant," Foster says.
Hibiscus plants thrive in more humid conditions, with humidity levels around 50 percent, Foster says. If you live in a hot and dry climate, you can help create that by placing your hibiscus near other plants or a water feature.
Get your hibiscus more sun
If your hydrangea plant is in a shady area, moving it to a sunnier spot in your garden or home will help it thrive.
Amend your soil
If your soil nutrients aren't meeting your plant's needs, adding a fertilizer with equal parts nitrogen, phosphorus, and potassium can help your hibiscus plant to thrive, Singleton says. This can be especially important if your plant is potted. "Plants kept in containers need regular applications of fertilizer to keep them happy and healthy," Foster days.
Address the insect issue
Aphids, mealybugs, and spider mites all respond well to some simple interventions. "Pests can generally be controlled with a good water spray to the leaves," Singleton says. "If this doesn’t clear up pest problems, an insecticidal soap can also help."
