There are few things more striking than the incredible blooms of the hibiscus plant. Whether in bright red or pink, or even yellow, these flowers create a stunning vision when grown in gardens or indoors.
However, many hibiscus grower’s seem to complain about one common issue, hibiscus yellow leaves. Not only are yellow leaves a little unsightly, but they’re usually a signifier of a deeper underlying issue that needs to be addressed.
Causes of Hibiscus Yellow Leaves
There are many factors that can cause leaves to be yellow, which also make them somewhat difficult to treat. Often, you’ll need to take every possible cause into consideration, make adjustments and see if your Hibiscus is improving.
Here are the most common reasons your hibiscus leaves are yellowing:
1. Nutrient Deficiencies in Hibiscus
Hibiscus plants grow best in very rich, nutrient-filled soil. When there is a lack of nutrients in the soil, the leaves will begin to become partially yellow, but they won’t necessarily drop off the plant.
If you suspect a nutrient deficiency, take extra care to feed your Hibiscus and replenish the soil. You can either re-plant your Hibiscus into fresh soil or support your soil with some extra fertilizer.
A low-phosphorus, water-soluble fertilizer is best. Either a 7-1-2 or 12-4-8 fertilizer is recommended.
2. Hibiscus Being Over or Under Watered
Watering is tricky because Hibiscus begin turning yellow both when the plant is over and under-watered. In general, hibiscus plants are thirsty and require very moist soil.
This is exacerbated in high-heat or incredibly windy environments. The trick here is to make sure your soil stays moist but not soggy. Waterlogged soil is equally as problematic.
Always make sure your Hibiscus has suitable drainage but that the soil remains slightly wet. A soil moisture meter is always a great tool to assist with this. Alternatively, you can also just stick your finger into the soil.
How Do I Know If My Hibiscus is Over Watered?
Again, a soil moisture meter is a sure-fire way to maintain the right amount of moisture. However, if you don’t have one handy, you can also check using your finger.
Simply press your finger into the soil, your finger should feel wet, but not too much of the soil should stick to your finger. Hibiscus plants will often produce Edemas as well.
These are small blisters or swellings which occur on the leaf stems. These are clear indications that the soil is waterlogged.
How Much Should I Water My Hibiscus?
Hibiscus plants can be watered as much as four times a week during the warmer seasons. However, when the plant enters its dormancy period in the cold months, you can almost cut that down completely.
Self-watering pots are great for hibiscus plants as they can then regulate the water level themselves.
3. Temperature and Weather Conditions
Temperature and weather conditions will also affect your Hibiscus. Extreme heat and too little water will almost always result in hibiscus leaves yellowing.
Equally so, a drop in temperature will cause the same effect. As a rule of thumb, bring your Hibiscus indoors in the wintertime to protect it. More so, keep it away from any overly drafty or windy spots.
4. Hibiscus Receiving Too Much or Too Little Light
Ensuring the right amount of light is also quite tricky. Too much or too little light will damage the leaves and cause little white spots along with yellowing.
In these situations, it’s good to monitor how much light your Hibiscus is getting during the day. If it’s too little light, move it to a sunnier spot. If it’s receiving too much light, move it to a shadier spot.
5. Hibiscus Leaves Yellowing Due to Pests
Pests can be a really tricky issue. Many houseplants suffer from invasions from pesky insects like spider mites, aphids and the like. If it’s a pest issue that is causing your hibiscus leaves to turn yellow, you’ll usually also notice a mottled underside.
Luckily, there are many fantastic home remedies and natural pesticides that can help curb the issue. Soapy water is a great go-to that will keep many pests at bay while still keeping your Hibiscus safe.
These are small, spider-like insects that live off the sap in plant leaves. They appear as tiny white or yellowish insects and leave behind a distinctive soft, silken webbing on the plant leaf.
Hibiscus leaves yellow and the plant will wither and die, so it is essential that you treat a spider mite infestation quickly with a general-purpose insecticide or Neem oil for about 64 days to kill the adults and eggs.
Another sap-sucking insect, these tiny flying pests look like their name – small, white flies. You can effectively prevent and treat these infestations by encouraging natural predators like ladybugs, green lacewings and pirate bugs, and by feeding your Hibiscus well in spring and summer.
Insecticides don’t work on whiteflies, but you can place reflective items (foil, CDs, etc.) around the plant to discourage them or use Neem oil.
The most common sap-sucking pest is the aphid, and you can spot them as clusters of small insects on tender growth. They drop a sticky substance called honeydew and are often accompanied by ants who consume this liquid.
You can introduce predator insects to your garden to eat the aphids (ladybugs and lacewings) and plant fennel, aster, cosmos, larkspur, verbena, hollyhock, dill, yarrow and mint to draw aphids away from your Hibiscus.
Garlic and onion plants will drive aphids away. You can also use Neem oil or wash the aphids of with a mix of liquid dishwashing soap in water. Insecticide is not recommended as this tends to kill predator bugs, so the harmful pests usually increase in number!
These insects are easily identifiable from the hard, cotton-like cottony or waxy cover to protect themselves once they’ve settled on a plant. Like aphids, they also produce honeydew.
Adults need to be removed by hand and, while encouraging beneficial insects does a lot to control mealybugs naturally, you may also need to use Neem oil.
6. Hibiscus Diseases Causing Yellow Leaves
There are also a few hibiscus diseases that cause yellow leaves. This can either be fungal infections, mildew, root rot or even bacterial blight.
In these instances, leaves will also begin to develop brown spots. In order to treat these issues, you can use a herbal fungicide or neem oil. Oftentimes, simply improving the soil conditions can also help the issue.
Diseases tend to spread all throughout the plants even before the leaves start to turn yellow. Typically the fungal diseases of Hibiscus are because of Phyllosticta, Cercospora, and Cladosporium fungal species.
This starts as white spots that turn grey, stunting the growth of your plant and is often the reason for Hibiscus leaves turning yellow and dying.
It is very common in environments where there is a lot of humidity. Although it’s not usually fatal, you want to deal with this issue before it stunts your Hibiscus and spreads to affect other plants.
You can use neem oil, a spray of baking soda, water and vegetable oil, and a commercial fungicide (a last resort, as these are harmful to the environment and not always effective on established powdery mildew).
If a Hibiscus is overwatered or living in boggy, poor-draining soil, the roots become infected with fungus and start to rot. One symptom of this is Hibiscus yellow leaves.
The best thing to do is to improve the soil quality, adding lots of organic compost and bark to help improve drainage. You should also reduce watering and only water when the first inch of soil appears dry.
Bacterial and Botrytis blight
This bacteria causes discolored and spotted flowers as well as discolored shoots and yellow leaves on Hibiscus. Prune away any affected growth and prune back plants that are crowding the Hibiscus to create better airflow.
It’s also advisable not to over-feed your Hibiscus and to avoid over-watering, as the increased humidity encourages bacteria growth. One of the most beautiful parts of a hibiscus is their flowers.
The reason behind this is because they are colorful and large, which is very inviting to pollinators and as well as to unwelcome insects, including root knot nematodes, and scale insects. (Learn more about root knot nematodes here).
For people who don’t know, scale insects are feeding on plants by piercing their stylets into the soft tissue of the plant. The stylets will then act as straws to help the sap be drawn up.
A smaller number of scales may have little to no effect to your hibiscus, but once they start to multiply, the leaves will start turning yellow and prematurely drop on the ground.
The nematodes, on the other hand, are worms that look like eels that are small. They usually feed on the plant’s roots.
They will then cause knotty galls, which will act to impair the function of the plant. This will then turn the leaves to start wilting and turn yellow.
When using a fungicide, it would be best to read the labels if it is safe for the plants that you have, since there are Hibiscus species that are sensitive to chemicals.
Hibiscus Frequently Asked Questions
Should I Remove Yellow Leaves From My Hibiscus?
Unfortunately, leaves won’t be able to recover once they’ve turned yellow and eventually, they will all drop off. Luckily, hibiscus plants are well-known to bounce back, and you should have fresh green leaves growing again in no time.
The most important thing is to first fix the issue with your Hibiscus and then remove the leaves. Be sure to use a sterilized blade when removing leaves so as to not spread any diseases across plants.
How to Revive Yellowing Hibiscus Plants
The best way to revive your Hibiscus is to restore balance and nutrients. Once you’ve identified the issue, you can act accordingly. However, for the best results, you can also consider:
- Re-potting the entire plant into a new container.
- Filling the pot with rich, fresh soil with a slow-release fertilizer.
- Changing the location of where your Hibiscus is growing.
If you are noticing that poor growth and a lack of flowers, even after you’ve revived your Hibiscus, then consider adding a 1-inch layer of compost and manure around the base of your plant.
This will help to give it an extra boost and hopefully ensure some beautiful blooms in the future.
Are Coffee Grounds Good for Hibiscus Plants?
Hibiscus plants enjoy slightly more acidic soil, which means that coffee grounds are really great when added to the soil mixture.
Is Vinegar Good For Hibiscus Plants?
Vinegar can also help to boost soil acidity. However, always use vinegar in moderation. Too much may stunt the plant growth. One cup of Vinegar to 1 gallon of water is recommended.
Is Epsom Salt Good For Hibiscus Plants?
Epsom salts are rich in magnesium and sulphur, which help your hibiscus plant absorb nutrients better. Stir some Epsom salt into the water and use this occasionally when watering your plants. This should also encourage flowering.
For a more comprehensive guide on hibiscus, here's is our complete growing guide for Hibiscus syriacus.
Now You Know What Causes Hibiscus Yellow Leaves
As long as you maintain the right amount of soil moisture, light and soil nutrient-rich, you really shouldn’t have too many issues with your hibiscus plants.
Hibiscus plants are quite resilient and should be back to their bright, blooming selves in no time! If you are unsure as to what may be causing yellow leaves on hibiscus, go through a trial and error period.
Fix one environmental condition at a time and continue to monitor your plant for any hibiscus yellow leaves.