Yellowing of leaves in plants is known as chlorosis. Green leaves starts to lose their color due to lack of pigment called chlorophyll.
University of Illinois, states chlorosis can be caused due to nutritional deficiency or environmental stress. (Source)
In simple words:
Your hibiscus plant leaves are turning yellow because of low sunlight exposure, drastic climate change, over-watering, under-watering, insufficient sunlight, pest or insect problems, diseases or something else entirely.
However, if only lower leaves of your flowering plant are turning yellow, then it can be part of natural process.
To find, you must diagnose your plant leaves and check if there is no serious issues.
Before that you must know essential requirements for growing hibiscus plant.
Know Your Plant – Hibiscus
Perennial and tropical hibiscus are two types of hibiscus plants that add aesthetic allure to your gardening space.
You can grow this flowering plant outdoors, but need to bring indoors in winter.
Tropical hibiscus plants can be left outdoors in the winter in USDA zones 10-12.
Perennial hibiscus can survive winters in zones 4-9.
- Hibiscus prefers a full-sun location with 5-6 hours of sunshine per day, but it can tolerate partial shade as long as it gets some bright sun.
- This plant enjoys frequent watering to keep the soil moist, however you should avoid overwatering or underwatering your plant.
- Growing soil should be acidic soil with a pH of about 6.0, although it can tolerate a pH range from about 5.5 to 7.5.
- To increase blooming you should fertilize the plant monthly during growing season with potassium rich liquid fertilizers.
- Potting soil should be well-drained with well rotten compost.
- Ideal temperature to grow topical hibiscus is 60-90F. However, you should protect the plant from scorching afternoon sun with a shade cloth.
Why Are My Hibiscus Leaves Turning Yellow?
Insufficient watering, low levels of nutrients, inadequate sunlight, over fertilization, cold climates, insects pests or diseases can held responsible for discoloration of hibiscus leaves and in some cases it also cause black spots on leaves.
As a gardener you must initially diagnose the cause and fix it so your hibiscus will thrive again.
Overwatering – Excess water results in root rot and yellow hibiscus leaves
Signs of overwatering: Yellow leaves, root rot, green algae layer on top layer of the soil.
This flowering plant doesn’t like to sit in water. Excess water left in the potting soil can drown out the roots and preventing them from getting enough oxygen.
Overwatering issues raises when potting soil fail to drain excess water.
So, it is important to make sure the soil is not overly saturated and that it drains well so that oxygen can reach the roots.
If plants are overwatered, they can suffer from root rot and other diseases. Not just that, overwatered hibiscus plants can be more susceptible to fungal and bacterial infestation.
How to revive?
Remove your hibiscus plant from the pot and shake off the excess soil.
Examine the roots, if there are any damaged roots cut them off and repot in a better growing soil.
Ensure the plant gets enough sunlight. Also, regulate your watering frequency. Water the plane only when it needs.
You can check the soil moisture by inserting your index finger into the soil.
In case, if the roots are damaged completely, then you have no choice but to discard the plant and start with a new plant.
Also Read: How to Grow Everlasting Sweet Peas?
Underwatering – Drought Stress
Underwatering, dry winds and potting soil that don’t retain moisture can result in drought stress.
Signs: This can be identified by the soil becoming dry and hard, with leaves appearing wilted or drooping.
Underwatering can cause hibiscus leaves to turn yellow, as the plant is not receiving the adequate amount of water it needs to stay healthy.
How to revive?
Reviving an underwatered plant can be done by providing it with enough water and allowing the soil to absorb the moisture.
This should be done slowly, as giving a plant too much water at once can cause it to become overwatered.
Sunlight – Avoid too much sunlight or low sunlight
Plant leaves need sunlight to make its food.
Only with adequate amount of sunlight, plant produces a pigment called chloroplast, which is responsible for green foliage.
When your hibiscus plant doesn’t get enough sunlight, it starts to turn yellow.
Similarly, exposure to too much sunlight can also cause hibiscus leaves to turn yellow.
When a plant receives excessive levels of sunlight, the leaves can become scorched and dry, leading to yellowing.
Remember this: Too much shade can turn hibiscus plant yellow. (Source)
How to revive?
Depending on your climatic conditions, hibiscus plant need 6 hours of full sun.
Relocate your container to a better location that gains direct bright sunlight.
With enough sunlight, your plant will bounce back to its natural color.
Soil – Choose well-drained potting soil
Most gardeners face overwatering garden problem. It is due to choosing wrong potting soil while.
Your growing soil should drain excess water and at the same time it should retain moisture.
Apart from this, ideal soil pH (6.5 to 6.8) should be maintained for healthy growth of the plant.
How to revive?
Perform soil test to check its pH and add perlite, vermicompost and sand to improve soil ability to drain excess water.
Over-fertilization – Avoid phosphorus buildup
Often gardeners over fertilize flowering plants to boost blossoms.
But, anything in excess isn’t good for the plant. Over fertilization can cause discolored hibiscus leaves.
Similarly, low levels of nutrients in the soil or not feeding your plant with enough fertilizer can also cause yellowing of hibiscus plant leaves.
For instance, copper and zinc are trace elements needed for plant. Deficiency in copper can make hibiscus leaves turn yellow and fall off.
Not just this, deficiency in nitrogen, potassium, magnesium, iron and manganese can result in yellow hibiscus leaves. (Source)
How to revive?
Hibiscus plant needs 16 essential elements to grow healthy and bloom.
Of them nitrogen, phosphorus, potassium and magnesium are essential for plant growth, root formation, to bloom and helps in food absorption.
Be sure to avoid over-fertilizing, as this can cause nutrient burn in your plants.
Pests – Check your plant regularly to avoid insects
Aphids, spider mites and mealy bugs are common pests that can cause yellowing of hibiscus plant leaves.
To get rid, use an insecticidal soap or neem.
If you’re using any chemical incorporated insecticide follow the directions on the package and take proper safety.
With regular care you can easily avoid hibiscus plant diseases.
Anyway, diseases such as leaf spot, canker and rust can cause chlorosis in hibiscus plant.
Inspect the plant leaves at regular intervals, if you notice any disease affected leaf or stem, then cut it off to avoid the spread of disease.
If you prune your plant incorrectly, it can result in yellow leaves.
Over pruning or pruning at the wrong time of year can shock hibiscus plants and cause discoloration of the leaves.
To avoid this, prune your hibiscus plants in late winter or early spring when they are dormant.
Why are my hibiscus leaves turning yellow and falling off?
In short, when plant undergoes drought stress, environmental stress like low sunlight or pests infestation, leaves start to lose their color and turn yellow.
Discolored leaves are left with less food and energy.
Due to this they start to fall off.
Important Tips for Growing Hibiscus Plant
Hibiscus plants are known for their vibrant and lush foliage, making them a great addition to any garden.
But in order to keep your hibiscus looking its best, there are some important tips you should follow.
- Select the right soil – Make sure to use well-draining soil with a pH level between 6.5 and 6.8 as this will provide optimal growing conditions for your hibiscus plant.
- Sunlight – Hibiscus plants need lots of direct sunlight in order to thrive. Place them in a spot that receives at least 6 hours of full sun per day.
- Watering – Water your hibiscus regularly and deeply, about once or twice a week depending on conditions such as temperature and soil type.
- Fertilize correctly – Determine the ideal fertilizer for hibiscus plants, then apply according to package directions, avoiding over fertilization which can cause nutrient burn in your plants.
- Watch out for pests – Keep an eye out for signs of pests such as aphids, spider mites and mealy bugs; if present, use insecticidal soap or neem oil to rid your plant of them safely and effectively.
- Prune properly – To avoid yellowing leaves due to shock from improper pruning techniques, only prune during late winter or early spring when the plant is dormant.
- Monitor for diseases – Keep an eye on your plant’s overall health to prevent any diseases from taking hold. If you suspect a disease is present, contact your local extension office for advice and treatment options.
How do I know if my hibiscus is overwatered?
Yellow leaves, algae layer on the top soil, yellow patches and rotting smell from drainage hole are signs that your hibiscus plant can be overwatered.
Should I cut off yellow leaves on hibiscus?
Yes, you should cut off yellow leaves on hibiscus. It is important to remove any dead or dying foliage from the plant so that it can focus its energy on new and healthy growth.
How often should you fertilize hibiscus plants?
You should fertilize hibiscus plants with a balanced fertilizer twice per month during the growing season.
You can use liquid fertilizer to enrich hibiscus plant.
There are various factors that turn green foliage of hibiscus to yellow. As a gardener you must first diagnose your plant properly and then find the right solution to revive it.
As mentioned, in-frequent watering, inadequate sunlight, choosing wrong potting soil, pests, diseases, too much or no fertilizing are the most common reasons for yellow foliage.
Khaja Moinuddin, a computer science graduate, finds joy in gardening and homesteading. Join him on this blog as he shares his experiences in homesteading, gardening, and composting