11 Reasons Your Hibiscus Has Yellow Leaves This Season
Does your hibiscus have yellow leaves? There are a number of reasons this can happen, and many of them can be corrected. In this article, gardening expert Melissa Strauss looks at the common reasons this happens, and how to correct it.
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If your hibiscus is turning yellow, it could be due to dormancy, sunlight, or watering issues. Some of these reasons are very little cause for alarm, while others will require a shift in the plant’s care, treatment, or environment.
Hibiscus has become a popular plant because of its extraordinary flowers. Though they only bloom briefly, tropical varieties have a year-round blooming season. They come in many vibrant colors, such as pink, orange, red, yellow, and even purple. These sun-loving, low-maintenance shrubs are a favorite for gardeners looking to add a touch of paradise to their space.
The good news is these plants are quite tolerant and resilient plants and they adapt well to a variety of conditions. Chances are, if your hibiscus leaves are turning yellow, all that is needed is a tweak in your care routine. Let’s dig a little deeper into potential reasons why your shrub’s foliage might be yellowing.
The Plant is Going Dormant
While commonly associated with tropical climates, many hibiscuses are considered perennial plants that will go dormant in winter. Only true tropical hibiscus plants are evergreen, while the hardy varieties lose their leaves in the fall.
This type of leaf yellowing predominantly pertains to cold-hardy varieties planted outdoors in climates that experience freezing winter weather. Hibiscuses detect the shift in daylight, as well as temperature. Just like other deciduous and perennial plants, they prepare for dormancy.
If your hibiscus’s leaves turn yellow as the weather cools, this is a natural chemical reaction as the plant prepares itself for winter dormancy. There is nothing to worry about, as leaves will re-emerge in the springtime as green as ever.
How to Fix
No fix! This is a completely natural part of your cold-hardy hibiscus plant’s life cycle. As your plant grows, the foliage will naturally turn yellow, drop, and new leaves will grow in their place in the spring.
Not Enough Sun
Hibiscus plants are sun lovers. They perform best when they get 6 or more hours of sunlight per day. Morning sun is best, so look for a spot that gets 6 hours as early in the day as possible.They can survive in part shade, but an effort should be made to get as close to the 6-hour mark as possible to maximize the blooming potential.
If a hibiscus is not getting enough light, it will not produce enough chlorophyll to support its foliage. When the plant’s interior leaves turn yellow, it could indicate a lack of exposure, as these are the most likely to be deprived of light.
How to Fix
Relocate the hibiscus to a spot that receives at least 6 hours of sun. This is easier for potted hibiscuses. If more exposure can be created without moving (ie. pruning a nearby shrub), it will benefit from staying put. However, this is rarely the case. Transplanting a grounded hibiscus will help the plant thrive, but you will have to do so carefully.
Too Much Sun
Too much sun can also be an issue for hibiscus, specifically during hotter summer months. The afternoon sun is hotter and more intense than the morning sun, so a plant that is getting a lot of afternoon exposure is more susceptible to this kind of damage than one that gets more morning sun with some shade in the afternoon.
Sun damage looks different from other leaf challenges. Excess sun will cause the leaves to look bleached and wilted. If you notice lightened spots on the foliage, particularly the leaves receiving the greatest amount of exposure, your plant is probably sun-stressed.
How to Fix
Potted Hibiscus: Move the plant to a location that gets less of that hot afternoon sun.
Grounded Hibiscus: Provide your plant with some shade. Plant something larger and more tolerant of the light in a position that offers some shade to the hibiscus. If this is not an option, transplant the hibiscus. Look for a location that receives most of its light during early parts of the day for around 6 hours.
Too Much Water
Overwatering and poor drainage can cause hibiscus leaves to turn yellow. Too much water reduces nutrient intake. This causes a deficiency that will result in the yellowing of the hibiscus leaves furthest from the source of nutrients, the soil. If an overwatering habit has been established, it should be corrected.
Soil that remains soggy can also result in root rot, which will have a similar effect. The roots decay and cannot absorb the necessary nutrients, water, and oxygen to sustain growth. An overwatered hibiscus or one with root rot will turn yellow and ultimately drop leaves.
How to Fix
Hold back on watering your plant. In times of average rainfall, a hibiscus only needs to be watered when the soil starts to dry out.
Drainage can be increased in an area by amending the soil with coarse sand or other large particles. This may work temporarily, but over time, the issue could (and probably will) reoccur. The best solution is to locate a spot with better drainage and move the plant. You can also divert water that may be draining improperly.
Underwatering
Underwatering can result from drought or simply neglecting to monitor the soil. Often, underwatering and overwatering can manifest similar symptoms. This, indeed, can be the case with hibiscus plants. Many hibiscus varieties are tropical plants, which means they like a lot of water. The soil should stay moist about an inch below the surface.
An underwatered hibiscus will initially show signs of dehydration by turning yellow and then brown, falling leaves. A chronic lack of water will stunt the plant’s growth, inhibit blooming, and ultimately result in the whole plant death as it will be unable to produce chlorophyll.
How to Fix
Indoor Hibiscus: A proper watering routine is very important. Soil that is consistently moist, but not soggy, is best achieved by regular watering and proper soil drainage.
Outdoor Hibiscus: Supplement watering during drier or hotter weather. Water the plant in the early morning from the base of the plant.
Lack of Humidity
As tropical and semi-tropical plants, hibiscuses need an adequate humidity level to truly thrive. In nature, these plants get water, not only from their roots but through their foliage by way of ambient humidity.
Low humidity is a common issue for indoor plants, as most folks prefer a lower level of humidity in their home. A lack of humidity can lead to yellowed and dried-out leaves and a lack of overall health. This discoloration will typically show first on the borders of the leaves.
This will specifically affect the moisture level of the leaves, causing them to turn yellow and brown at the edges. Hibiscus plants perform best at humidity levels between 50-80%.
Plants, especially tropical plants that are native to humid climates, take in a lot of moisture through their foliage. When humidity is lacking from the air around them, their flowers are the first thing to suffer. A lack of humidity will cause bud drop and accelerate wilting, shortening the life of the blooms.
How to Fix
Indoor Hibiscus: Increase the humidity around the plant. This can be done by moving the plant into a more humid space, such as a bathroom. Other great options are to use a humidifier, or a pebble tray, to raise the humidity specifically around the plant. You can also give your hibiscus a mist here and there.
Outdoor Hibiscus: If you live in a dry climate, hibiscuses might not be the best plant for your garden. But that doesn’t mean you can’t cultivate one of these pretty plants. It will just need to be a houseplant in most cases.
Nutrient Deficiency
A common and generally easily correctable reason for hibiscus leaves turning yellow is nutrient deficiency. This especially pertains to hibiscus plants in containers. These plants generally bloom for a long time and produce a great number of flowers. Therefore, they use up a lot of nutrients during their blooming season. Research shows that nitrogen, phpshorus, iron, and calicum are the most common deficiencies.
If the yellowing of leaves happens while the hibiscus is in bloom and appears to be starting at the ends of the leaves, it could be a nutrient deficiency. This will show first in the parts of the plant that would be the last to receive nutrients from the soil. If there is not enough to go around, the plant will begin to look malnourished.
If your hibiscus leaves are specifically turning yellow but retaining green veining, the issue is almost certainly an iron deficiency. This is a soil pH issue and means that the soil is not properly acidic to break down the iron so that the plant can utilize it.
How to Fix
Fertilize potted hibiscus plants once a week while in bloom. For plants in the ground, once every two weeks should be adequate. For a proper balance of nutrients, try using a 12-4-8 or 17-5-24 fertilizer.
If soil pH is the problem, add some organic matter such as compost to the mix. Commercially available soil acidifiers will have a similar effect.
Hot Weather
A heatwave in the late spring while the weather has been cool or in the fall after the temperatures have begun to drop, can cause stress to your hibiscus. Keeping an eye on the temperature is an accurate way to diagnose this issue.
Heat stress will typically affect the leaves that don’t get as much sun, as these leaves are less accustomed to the heat. The leaves on top that get plenty of sunlight will be accustomed to more heat, so the shift in temperature will not affect them as dramatically.
Water is of utmost importance during times of extreme heat, which can cause water to evaporate faster. The soil around your hibiscus should not be allowed to dry out, as this can stress out the plant even further.
Heat stress will show itself by the hibiscus leaves turning completely yellow and then browning. This will affect the leaves toward the bottom and sides of the hibiscus, where the sun reaches the least. The leaves will take on a wilted appearance, and ultimately the plant will lose some leaves.
How to Fix
Potted Hibiscus: Temporarily relocate your plant to a space with more shade. If the heat wave sneaks up on you, move the plant as soon as you recognize the shift. This short-term sun deprivation will do far less damage than heat stress.
Grounded Hibiscus: Create some temporary shade for the plant. Keep the soil moist to help the plant to stay hydrated, adding some protection from the drying effects of the heat wave.
Freezing Temperatures
An early freeze, or a freeze in a climate that doesn’t typically experience that type of weather, can cause a hibiscus to turn yellow and lose its leaves. This is more of an issue for tropical varieties, as these plants are not cold-tolerant.
How to Fix
Monitor the weather to proactively manage this issue. If your region is expecting unseasonably cold weather, take measures to protect your plants. Use frost cloth to help keep the dew off the foliage and prevent the most severe kind of leaf damage.
Simply bring potted hibiscus plants indoors during the freezing weather. Make sure that for plants in the ground, you purchase plants that can survive the winter in your climate zone.
Simply bring potted hibiscus plants indoors during the freezing weather. Make sure that for plants in the ground, you purchase plants that can survive the winter in your climate zone.
Stress
Stress of all kinds can cause leaf damage. We have seen this with heat and cold, as well as water issues. Another common type of stress is that caused by changing the plant’s environment. This typically happens with transplanting, and when container plants are moved inside or back outside because of weather shifts.
Consistency is key to avoiding stress. A certain amount of leaf drop cannot always be avoided in these conditions. When a plant is transplanted, it goes through stress, and some leaves will almost certainly be lost.
How to Fix
Minimize stress from transplanting by keeping as much of the root system intact as possible and thoroughly watering the root ball before planting. Give the plant some additional nutrients during this process to also help the plant to recover faster.
Make gradual shifts when moving a potted plant indoors or out for seasonal purposes. Try to move the plant when the outside temperature is closest to the temperature indoors and provide your plant with adequate humidity upon moving indoors.
Insect Infestation
Several types of insects that like to feed on the sap of hibiscus leaves and flowers. Whiteflies, mealybugs, aphids, and spider mites can all be culprits of yellowing leaves, as they drain the plant of nutrients. As we discussed, nutrient deficiency is a common cause of yellowing foliage.
If you notice, along with turning yellow, the leaves of your hibiscus are beginning to shrivel and curl under, there is probably an insect issue. Inspect the undersides of the leaves for other evidence, such as insects themselves and sticky residue left behind by many of these garden pests.
How to Fix
Indoor Hibiscus: Prevention is the best medicine when it comes to houseplants. Inspect new plants for signs of insect damage to drastically reduce their occurrence. If some sneak past your roving eye, isolate the plant immediately and treat it with neem oil, horticultural oils, or insecticidal soaps.
Outdoor Hibiscus: These obviously can’t be isolated but should be treated as soon as possible using the same methods. Most plants will need to be treated more than once to eradicate all generations of insects. Wait two weeks and treat a second time to ward off another infestation.
Final Thoughts
If you find your hibiscus leaves are turning yellow, consider the time of year, the amount of water the plant is receiving, and any environmental shifts that could be causing stress to the plant. Take heart, as a hibiscus can make a comeback from just about everything on this list by providing it with a little extra care.
