The Hibiscus tree belongs to a group of flowering plants in the mallow family Malvaceae.
It is local to warm temperate, subtropical and tropical counties in California, Texas, Florida and other tropical countries around the world.
Hibiscus leaves turning yellow is a common problem, but not one you should be too concerned with.
If your Hibiscus leaves turn yellow, it means your Hibiscus is trying to tell you it needs something.
Ask yourself these seven questions to determine just what the problem may be causing yellow leaves.
#1 – Is My Hibiscus Getting Enough Nourishment?
If your Hibiscus leaves are turning yellow but not falling off, this can be a signal your plant has a nutrient deficiency, experiencing iron chlorosis, and needs a dose of fertilizer, Epsom salts or a soil amendment.
#2 – Hibiscus Leaves Turning Yellow – Am I Watering Correctly?
The leaves of tropical hibiscus plants may turn yellow if the plant gets too much water, or if the plant does not get enough water.
Remember, Hibiscus plants need lots of water, even more so when it is a potted Hibiscus, in a windy location or very hot.
Nevertheless, if you water too much, plants can experience problems with root rot.
The idea is to maintain consistently moist soil around Hibiscus plants.
Be careful not to keep the soil too soggy.
During your tropical plant’s dormant period, you should avoid overwatering it.
Little water is enough to keep the soil from becoming completely dry because it may lead to wilting.
Always be sure to provide good drainage.
If your plant is not planted in well-draining soil or does not have good drainage holes in its container, the ground will be soggy.
It will cause yellow leaves and damage to the root system.
To ensure your plant is getting enough water, check the soil every day or two by poking your finger into the top inch or so.
The dirt should feel slightly moist, not wet.
When it begins to feel dry, it’s time to water. You may also wish to invest in a self-watering pot to provide consistent watering.
There are also many high-tech aids like large self-watering planters to help you keep track of your plants’ watering and fertilizing needs.
Inadequate fertilization, especially lack of nitrogen, may be the cause for rose of Sharon leaves turning yellow. However, don’t overdo it, as too much fertilizer can scorch the foliage and cause yellowing. Excessive fertilizer can also burn the roots and damage the plant. Apply fertilizer only to moist soil, and then water well to distribute the substance evenly.
#3 – Am I Keeping My Hibiscus At The Right Temperature?
Hot weather can cause yellow leaves on Hibiscus because plants need extra water during warm, dry weather.
If your plant is too dry, you will initially notice the leaves turning yellow and falling off.
If you don’t attend to its special watering needs in the summer heat, the entire plant will dry up and may die from heat stress.
Hibiscus tree is also not tolerant of freezing weather. When the weather turns cold, the leaves will turn yellow and fall.
Remember, Hibiscus plants are not frosting hardy, so bring outdoor plants in when a freeze is expected.
Drafts can cause yellow leaves and leaf drops. Hibiscus planted outdoors should be sheltered from the wind.
Hibiscus kept as houseplants should be protecting from drafts.
#4 – Is Your Hibiscus Getting The Right Amount Of Light?
Just as with water, too much or too little, only enough light can cause Hibiscus new leaves to turn yellow.
Excessive sunlight results in leaf sunburn which manifests as white spots on the leaves.
If this happens, you should prune off the damaged yellow leaves and move your plant to a location where it can get partial shade during the hottest part of the day.
Too little light can also cause discoloration and falling leaves.
If this is the case, you’ll need to move your plant to a setting where it can get ample full sun.
#5 – Is it Time For My Plant To Go Dormant?
The Hibiscus’ growing season is spring, summer, and fall.
At the end of the autumn, leaves may begin to start turning yellow and fall.
This means your plant wants to go dormant, so you should reduce the amount you are watering and allow your plant to take a rest.
#6 – Is My Hibiscus In The Right Place?
During your plant’s period of dormancy, bring it into the house and keep it in a cool and dark area for about two months.
The environmental changes may affect hibiscus.
Toward the end of the dormancy season, cut the plant back and put it in a bright, sunny window.
Begin regular watering, and soon you’ll see new growth appear.
When this happens, start fertilizing your Hibiscus.
In the springtime, take your plant outdoors if you wish.
Moving plants from indoors to outdoors may cause yellow leaves, cessation of blooming, and a wilted appearance.
These are all signs of stress.
To minimize this, transition your plant gradually from indoors to outdoors at the beginning of the growing season.
#7 – Are Pests Attacking My Hibiscus?
If leaves turn yellow and take on a mottled appearance with signs of injury on the undersides of the leaves, it is because of the infestation of spider mites.
Rose of Sharon is relatively pest-resistant, but pests such as aphids and whiteflies may be a problem. Both suck the juices from the plant, which can cause discoloration and yellowing rose of Sharon. These and other sap-sucking pests are usually easily controlled by regular applications of insecticidal soap or horticultural oil. Remember that a healthy tree, properly watered and fertilized, is more resistant to infestation.
To eradicate these pests, spray the entire plant with a solution of soapy water.
Spray the entire plant daily until the pests disappear.
Following this, give your plant a good rinse to remove soapy residue.