By Nikki Phipps
(Author of The Bulb-o-licious Garden)
Hibiscus yellow leaves are common and usually not anything to worry about. Oftentimes, hibiscus leaves turning yellow will correct itself. In some cases, pruning of the entire plant is necessary.
What Causes Hibiscus Leaves Turning Yellow?
The hibiscus leaf turns yellow as a way of signaling a specific need. Many factors contribute to hibiscus leaf yellowing. Becoming familiar with these factors allows you to fix the underlying issue before it becomes a problem.
Nutrient deficiency causing hibiscus yellow leaves
If your hibiscus is suffering from a nutrient deficiency, the leaves will turn partially yellow but remain on the plant. This can be easily corrected by adding fertilizer or amending the soil.
Watering causing hibiscus yellow leaves
Too much water or not enough can result in hibiscus leaves turning yellow. While hibiscus plants require lots of water, especially during periods of excessive heat or windy conditions, overwatering can be detrimental. Ideally, you should water just enough to keep the soil moist, not soggy.
Watering should be backed off during dormancy. Wet the soil just enough to prevent it from drying out completely. Inadequate drainage can also affect the hibiscus and yellow leaves often result. Make sure containers provide suitable drainage. Failing to give hibiscus plants enough water can also cause the hibiscus leaf to yellow. Check the soil with your finger to ensure the plant is getting enough water. Self-watering pots are also a good way to alleviate these problems.
Temperature causing hibiscus yellow leaves
When temperatures are extremely hot, especially in summer, the hibiscus requires additional watering. Otherwise, the plant will dry up quickly and succumb to heat stress. This can result in the hibiscus leaf turning yellow and eventually dropping off.
Likewise, when temperatures get too cold, the hibiscus will also respond with yellowing of its leaves. Ensure that the plant is kept away from drafty locations and excessive wind. Also, be sure to bring the plant indoors when outside temperatures reach freezing.
Light causing hibiscus yellow leaves
Light is another factor associated with the hibiscus and yellow leaves. Again, too much sunlight can result in hibiscus leaves turning yellow as well as the development of white spots, which signal plant burn. Remove the damaged leaves and change the location of the plant.
If the hibiscus is not getting enough light, the plant may also react with yellow leaves, which will begin dropping in order to make up for the lack of light. This can be easily remedied by moving the plant to an area receiving more sunlight. Yellow leaves can also be an indication that the hibiscus is ready to go dormant. Allow the plant to die down by reducing watering.
Location causing hibiscus yellow leaves
After allowing the plant to enter dormancy, bring it indoors and keep it in a cool, dark place for a couple months. Then cut the hibiscus back and place it in a sunny window. Resume regular watering. When the hibiscus shows new growth, give it a boost of fertilizer.
Once spring returns, the plant can be moved outdoors. If your hibiscus has yellow leaves, has stopped blooming, or looks wilted after moving it, the plant may be suffering from stress. This is a common occurrence and can be expected when moved to a different environment.
Pests causing hibiscus yellow leaves
In addition to yellowing, the hibiscus leaf may become mottled with markings on the underside. This can be the result of pests, such as spider mites. If left untreated, the stressed plant will eventually lose all of its foliage. If you suspect these pests, spray the plant with soapy water or an appropriate form of pesticide. However, take care not to overuse pesticide, as this may also contribute to hibiscus yellow leaves.