A vibrant display of bright and colorful hibiscus flowers can quickly turn lackluster when the leaves start turning yellow. This discoloration and yellowing of leaves is usually an indication of some underlying issue that needs troubleshooting. Here are the most common reasons behind hibiscus leaves turning yellow and how to fix them:
Overwatering
Excess moisture is one of the most common reasons for hibiscus leaves turning yellow. Hibiscus prefers well-drained soil and does not do well in wet conditions. Overwatering causes root rot leading to a lack of nutrients and yellowing of leaves.
How to fix it:
- Check how often and how much you are watering the plant. Hibiscus only needs moderate watering when the topsoil is partly dry. Water deeply only when the top 2-3 inches of soil are dry.
- Ensure the pot has enough drainage holes at the bottom. Use a potting mix meant for hibiscus or citrus plants, which drains well.
- Remove the plant from the pot and inspect the roots. Trim off any brown, mushy roots and repot with new soil mix.
- Allow the plant to dry out between waterings. Spread out watering to 1-2 weeks in winters when growth is slower.
- Move the pot to a sunny spot so the soil dries out faster. Provide good air circulation around the plant.
Underwatering
While overwatering is common, leaving hibiscus without enough water can also cause the leaves to turn yellow. Drooping, wrinkled leaves that turn yellow are a sign of underwatering.
How to fix it:
- Check the soil moisture by sticking a finger into the soil. Water thoroughly whenever the top few inches become partly dry.
- Set up a watering schedule based on your climate, season and the plant’s needs. Hibiscus needs more frequent watering in summer.
- Choose a pot with drainage holes to prevent waterlogging.
- Water slowly and deeply, until it seeps out of the drainage holes at the bottom. This encourages deep root growth.
- Misting and occasional showers don’t hydrate plants well. Stick to deep watering whenever the soil partly dries out.
Nutrient Deficiency
Lack of important nutrients like nitrogen, phosphorus, potassium, iron etc. can show up as yellow leaves in hibiscus. Nutrient deficiency hinders photosynthesis causing discoloration.
How to fix it:
- Use a balanced fertilizer with macro and micronutrients. Apply as per label instructions, usually biweekly in growing season.
- Check if the soil pH is in the ideal range of 6 to 6.5. Iron deficiency shows up if soil pH is too high.
- Look for signs of chlorosis – yellowing between leaf veins while veins remain green. This indicates iron or magnesium deficiency.
- For rapid greening, use iron supplements or chelated iron spray on leaves.
- Replant in fresh soil every 2-3 years to replenish depleted nutrients. Mix in compost or manure.
Poor Drainage
Excess moisture due to poor drainage has the same effects as overwatering. Root rot and lack of oxygen causes yellowing leaves.
How to fix it
- Repot the plant in a container with enough holes for drainage. Elevate pots above ground level.
- Use a free draining potting mix, not garden soil which retains water.
- Remove excess water from drainage saucers so the pot does not sit in water.
- Propagate new plants from cuttings in fresh, suitable soil if the current root system is damaged. Discard overly wet soil.
Sunburn
Too much hot sun can scorch and yellow the leaves of hibiscus. However, insufficient sunlight also causes yellowing. It’s about finding the right balance based on your climate.
How to fix it:
- Move potted hibiscus to a spot that gets 4-6 hours of sunlight, avoiding the hot afternoon sun.
- Gradually transition an indoor plant moved to full sun outdoor to prevent leaf burn.
- Provide shade using curtains or plant taller plants on the sun-facing side. Mist leaves to cool them.
- If yellowing is due to insufficient sunlight indoors, move the pot to the brightest spot.
- Supplement natural light with 4-6 hours of artificial grow lights directed on the hibiscus.
Pests
Sap sucking pests like aphids, scale, mealybugs and spider mites can all cause hibiscus leaves to turn yellow. They damage the plant tissue during feeding.
How to fix it:
- Check underside of leaves and new growth for presence of pests. Look for white spots, bumps, cottony webs etc.
- Remove pests by hand or use insecticidal soap sprays for heavy infestation. Spray neem oil solution as a natural pest deterrent.
- Attract predatory insects like ladybugs which feed on plant pests.
- Remove any heavily infested parts or severely damaged leaves which are unlikely to recover.
- Use row cover fabric or screens to prevent pests from reaching and infesting the hibiscus.
Fungal & Bacterial Diseases
Foliar diseases like leaf spot, powdery mildew, bacterial leaf blight or canker can lead to yellowing of infected parts of the leaves.
How to fix it:
- Prune off infected leaves or leaf sections to prevent spread.
- Use a fungicide or copper based bactericide spray as per label directions.
- Space plants out and avoid overhead watering to reduce humidity levels.
- Disinfect pruning tools to avoid transmission between infected and healthy parts.
- Remove crop debris and fallen leaves where fungal spores may persist.
- Grow disease resistant hibiscus varieties if your climate has frequent fungal issues.
Cold Weather
Hibiscus is a tropical plant that prefers temperatures between 60°F to 90°F. Cold snaps and frosts can damage leaves, causing yellowing and fall off.
How to fix it:
- Move potted hibiscus plants indoors or to a sheltered area when temps drop too low.
- Cover the plant with fabric row cover or plant blanket to shield it from frost.
- Avoid pruning in fall so leaves remain on the plant for protection. Prune damaged parts in spring.
- Maintain optimal temperatures and reduce drafts indoors during winter. Place pots on heating mats.
- Insulate roots by mulching beds with leaves or pine straw so roots don’t freeze.
- Once temps warm up in spring, damaged plants will recover new foliage.
By identifying the specific cause behind the yellowing leaves, you can take appropriate corrective measures to restore your hibiscus plants to their lush and colorful state once again. Pay attention to soil moisture, drainage, sunlight exposure, nutrients, and pest/disease prevention for happy, vigorous plants.
Frequently Asked Questions
What causes yellow spots on hibiscus leaves?
Yellow spots on hibiscus leaves are typically caused by fungal or bacterial diseases like leaf spot. Check for sunken lesions on the leaf surface. Prune off infected leaves to prevent spreading.
Why are my hibiscus leaves turning yellow and falling off?
Hibiscus leaves turning yellow and dropping indicates the plant is severely stressed. This could be due to overwatering, underwatering, temperature extremes, root damage from diseases, or nutrient deficiencies.
How do I revive a hibiscus plant with yellow leaves?
Revive a hibiscus plant with yellow leaves by first identifying and correcting the underlying issue, whether irrigation, sun exposure, pests, diseases etc. Then provide optimal care with adequate water, fertilizer, sunlight and pest prevention for new growth.
Should I cut off yellow leaves on my hibiscus?
It’s best to cut off severely yellow or damaged hibiscus leaves to prevent further stress on the plant. But leave leaves with minor yellowing so the plant can draw nutrition out of them. Remove fallen leaves promptly to prevent pests and diseases.
What nutrient deficiency causes yellow hibiscus leaves?
Iron, magnesium, nitrogen and manganese deficiency commonly cause yellowing of hibiscus leaves. Treat with a fertilizer containing these nutrients. Adding Epsom salts provides magnesium.
Can too much sun cause hibiscus leaves to turn yellow?
Yes, scorching sun can cause yellow or burnt looking hibiscus leaf margins. Move to dappled or partial shade. Mist leaves and provide shade cloth to prevent leaf sunburn.
Is yellowing of lower hibiscus leaves normal?
Some yellowing of lower leaves over time is normal as the plant drops old leaves. But if many leaves rapidly turn yellow, it indicates a watering, pest or nutrient problem that needs fixing.
Conclusion
Yellowing hibiscus leaves quickly ruin the ornamental appeal of this tropical flower. But the discoloration acts as an important visual cue that your plant needs help. By recognizing whether the issue is overwatering, pests, diseases, sun damage or nutritional causes, you can get your hibiscus back to vibrant good health. Pay close attention to proper planting conditions and care for your variety of hibiscus to prevent stressful conditions that lead to yellow leaves.