Hoya plants are a favorite among gardeners and homeowners because their extended lifespan and distinctive, green, vining leaves make them the ideal outdoor and indoor plants.
Hoya’s are often called wax plants because of their waxy nature, and some people call them porcelain flowers because of the unusual texture of the blossoms the plant grows.
Hoya plant care is not simple; only a few conditions must be met to keep the plant happy and prevent problems like hoya leaves turning yellow.
Let’s review these requirements and learn the reason behind hoya leaves turning yellow.
Reasons Behind Hoya Leaves Turning Yellow
Table of Contents
Below are some reasons why a hoya plant’s leaves may turn yellow, as well as steps you can take to eliminate these issues and encourage your Hoya plant to develop bright green and healthy foliage in a forest canopy.
Overwatering and Underwatering
Hoya plants are known for their bright green-colored waxy leaves. Therefore, if your hoya leaves turn yellow, that is a sign that the plant is not happy and that you are doing something wrong. Improper watering is one of the most common causes of a hoya plant’s leaves turning yellow.
If you supply too much or too little water to your hoya plant, it will communicate that to you through yellow leaves.
When you overwater your plant, the plant loses soil aeration. Every plant’s roots need oxygen to transport nutrients throughout the whole plant.
Overwatering a hoya plant results in its roots getting damaged and suffering root rot. Roots that have been damaged won’t be able to absorb the soil’s moisture.
This occurrence also causes the plant’s leaves to lose their strength, become discolored, develop more slowly, and eventually drop.
The damaged roots of overwatered plants cannot efficiently distribute nutrients throughout the plant, which is another reason behind the yellowing of leaves.
The yellowing of leaves usually affects the older leaves and gradually moves on to newer foliage if not tackled immediately.
Moreover, underwatering also causes leaves to discolor, wilt and dry. Water is essential for plants’ survival since every plant requires water to transport nutrients to its leaves and produce energy.
Underwatering can cause a plant to develop a nutrient deficiency, causing its leaves to turn yellow.
One way to ensure you are not overwatering or underwatering a hoya plant is to wait for the soil to dry up before watering your plant again since Hoya plants like dry settings.
Hoya plants require irrigation every 14 days in the summer and spring months and every 21–28 days during winter.
Therefore, if you feed a hoya plant more than once every 14 days throughout the summer and spring months, it is likely the cause of the yellowing of the foliage.
Here are a few simple measures you can take to ensure you are not overwatering or underwatering your hoya plant.
Examine the plant pot for drainage holes
Drainage holes are small holes under plant pots that allow the extra water to drain out of the plant after every watering and help ensure the plant does not drown or suffer issues like root rot due to the accumulation of excess water.
If your plant’s pot does not have drainage holes, the best thing you can do is to examine for root rot, remove the rotted roots, and re-pot the hoya plant in a new pot with proper drainage holes.
Moreover, sometimes individuals with busy schedules may forget to empty the cachepot or dip trays that sit under the drainage holes of their plant posts.
This can also result in the plant drowning and suffering significant damage due to being unable to dispose of the water it does not need.
Therefore, setting a reminder to empty the cachepots and dip trays after each watering is critical.
Establish a watering schedule
Proper watering techniques, such as maintaining a watering schedule, can assist you in adequately watering your hoya plant.
As previously stated, the amount and frequency of watering required by a hoya plant vary depending on the season.
So, adjust your watering schedules to the seasons and environment in which you live, and devise a suitable watering schedule on a planner or set reminders on your phone to remind you that you need to water your plant.
Avoid placing your plant in low-light areas
Having your hoya’s sit in low-light areas is also one culprit behind the plant exhibiting the symptoms of overwatering. When you place a plant in areas with optimal sunlight, the sunlight helps the plant’s soil dry up quickly, enabling the plant to get rid of any excess water.
If you place your hoya plant in an area with low light, the absence of sunlight may mean that the soil will stay wet for longer if you give the planter more water than it needs, which can then lead to hoya leaves turning yellow.
Using The Wrong Potting Mix
Like many other plants, a Hoya plant’s roots naturally grow into the cracks of the tree trunks instead of in the ground. This is why it is essential to use an aerated and well-drained potting mix made for Hoya plants or other plants similar to Hoya.
Since water-logged soil can hold water for extended periods, overwatering may not necessarily result from excessive water being given to the plant.
Excessive water retention in the soil will eventually cause the Hoya plant’s roots to rot, and if not identified early and remedied, waterlogged soil can eventually kill a hoya plant by severely damaging the roots and turning the foliage yellow.
If you think the reason behind yellow hoya leaves is that you have planted the hoya plant in the wrong potting soil, the best thing you can do is to immediately re-pot your hoya plant in an appropriate aerated and well-draining soil mix. You can easily find an appropriate soil mixture for hoya’s in your local nurseries.
Moreover, another option is preparing your potting mix if you can’t locate one appropriate for hoya plants or aren’t sure whether the one you have is suitable.
To make a DIY potting mix suitable for Hoyas, you must combine roughly 1/3 perlite, 1/3 compost for house plants, and 1/3 cactus mix.
This will help you prepare the ideal soil mixture for your Hoya plants.
Improper Lighting Conditions
Too little or too much light can also be another culprit behind the hoya plant showing signs of damage and causing yellowing leaves. Gap plants are another name given to hoya plants.
Hoyas utilize the sunlight seeping through the empty spaces above them in their natural habitat, which aids these plants in growth. The light falling on the earth in these areas is still slightly diffused due to the shade provided by the nearby vegetation and plants.
This is why hoyas are not well suited for exposure to intense sunshine. Therefore, if you have kept your Hoya pot in an area with strong direct sunlight, that might be the reason behind the yellowing leaves.
Since the initial indicator of poor lighting conditions might be the leaves’ green pigment getting even darker as your Hoya strives to capture the maximum amount of sunlight, low sunlight is not frequently one of the causes of Hoya leaves turning yellow.
However, if you keep your hoya in too little light, soon you will start to observe older foliage turning entirely yellow and falling off the plant since it won’t sustain all of its leaves for long under low sunlight.
Hoyas favor moderate to bright or indirect sunlight. Some Hoya plants thrive in approximately two hours of early morning or afternoon direct light. However, exposure to scorching direct sunlight may burn your hoya plants’ leaves and make them yellow.
Therefore, you must be careful that the direct sunlight your Hoya plants are getting is not too scorching. Furthermore, keeping an eye on your hoya plant for signs like drooping or the leaves turning pale green can also help you determine if your hoya plant likes direct sunlight or not.
If you notice yellowing leaves, changing the location of your hoya plant to a spot that gets indirect sunlight may be all you need to get the leaves back to a bright green color.
Covering a window with bright sunlight through curtains can also help you create partial shade and save your Hoya from sun damage if you don’t have any other space for your Hoya plant.
If your Hoya plant’s leaves are turning yellow because it receives little sunlight, you can change the plant’s location to a south-facing window with plenty of sunlight.
However, remember to keep the plant at a distance from the window or over the window with a light curtain to shelter the plant from direct sunlight.
Additionally, if you live somewhere that does not get a lot of sunlight or have long winter months with low sunlight, investing in plant grow lights can also help you provide your Hoya plant the light it needs to flourish.
Cold Drafts and Temperature Stress
Since Hoya’s native habitat is Australia, Pacific Islands, and Tropical Asia, making them tropical plants, Hoya does not like cold drafts and colder temperatures below 10°C.
Even though some Hoya plants may be able to survive if they are kept in cold temperatures for a short amount of time, it is not recommended to keep them out on cold nights since cold temperatures cause the plant stress.
When a Hoya plant is stressed, it will then exhibit signs of stress, usually in the form of yellowing leaves. In contrast to not doing well in colder temperatures, Hoya plants can do considerably well in hot temperatures and high humidity levels.
Hoya plants can easily survive temperatures up to 35°C without any issues. The only thing that may bother Hoya plants in hot climates is exposure to warm drafts. Warm drafts cause not only yellow Hoya leaves but also cause brown leaf tips.
The best way to keep your Hoya plant safe from cold drafts and temperature stress is to monitor the temperature. If you keep your Hoya plants outdoors, bring them indoors when winter approaches.
Moreover, keep your Hoya at a distance from open windows that might blow in cold air during the wintertime, and do the same during summers to protect your Hoyas from warm wind gusts.
Keeping your Hoyas away from coming in direct contact with the cold air from air conditioning units is also essential to keep the plant safe from going into shock.
Pests and Diseases
Even though it is easy to keep Hoya plants free of pests, a weak plant may be susceptible to pest infestations and diseases. If your Hoya plant is damaged or weak, it is susceptible to getting infested with pests like spider mites, mealy bugs, aphids, etc.
You can easily differentiate the yellowing of leaves caused by insects from the yellowing o leaves caused by other issues like overwatering since these sap-sucking insects feed on the leaves, leaving distinctive traces of yellow throughout the affected foliage.
Furthermore, the Hoya plant is less likely to catch diseases than other houseplants since the leaves’ wax protects the plants from diseases. However, mistakes like overwatering can make the plant susceptible to catching diseases and developing conditions like root rot.
Examining your Hoya plants regularly for pests and diseases is the best way to catch any pest infestations or diseases in the early stage.
Moreover, if you spot pests or signs of disease on your plant, the first thing to remember is not to panic since your Hoya plant can survive pests and diseases if you treat them immediately before they worsen.
The first step you need to take if you notice pests on your Hoya plant is to separate the affected plant from other plants to ensure the pest infestation does not spread to your other plants.
Next, you need to eliminate the pests with the help of an insecticide. Store-bought insecticides are made of harsh chemicals that can further damage your plant. Therefore, sticking to natural pesticides like neem oil is recommended.
Similarly, regularly check for signs of diseases on your Hoya plants. Brown, black or yellow spots on Hoya leaves are usually signs of disease.
If your Hoya plant is diseased, separate it from your other houseplants, carefully prune off the diseased foliage with sterilized pruning shears, and treat the plant with neem oil.
Hoya plants produce heavy foliage, which means that they require a good quantity of nutrients to thrive.
Yellowing leaves may sometime signal nitrogen or potassium deficiencies in Hoya plants. Magnesium and phosphorus deficiencies can also lead to the yellowing of leaves in plants.
Nitrogen is necessary for the foliage to create chlorophyll during photosynthesis. The green pigment in plants is called chlorophyll.
When your plants are deficient in these micronutrients, the foliage turns yellow, from the oldest to the youngest leaves.
The best way to separate the yellowing of leaves from issues other than nutrition deficiency is to look for signs like paler greenish-colored leaves and wrinkled texture, a common sign of nutrition deficiencies.
So if you think that nutrition deficiency is the reason your Hoya leaves turn yellow, you can give your Hoya plant an extra boost of nutrition through liquid fertilizer.
Even though you won’t be able to fix the yellow leaves, the new foliage that will grow will be a darker green color and look healthy.
Moreover, an appropriate soil mix for Hoya plants is all you need to supply the plant in its first two years of life since Hoya plant soil mixes sold in the market are usually stocked with all the nutrients the plant needs to stay healthy.
However, you can supplement the plant with extra nutrients from a moderate-strength fertilizer every few months (preferably 4-6 months) to help the plant flourish.
Nutrient deficiencies can also occur in Hoya plants if you fail to change their pot to a larger pot every few months.
When a plant overgrows a pot, it can quickly absorb all the nutrients from the soil mix in the pot and later suffer nutrient deficiency since the soil mix in the point does not provide enough nutrients it needs to thrive.
The early spring and summer months are the best time to re-pot your Hoya plants. So if you feel your plant has outgrown its pot, it may be best to get a larger pot with drainage holes and a well-draining soil mix appropriate for Hoya plants and transfer your Hoya plant into its new pot carefully.
Now that you know all the reasons behind Hoya leaves turning yellow, you can diagnose why your Hoya plant is exhibiting yellow leaves and remedy the issue with the help of the solutions discussed above.
You can eliminate yellow Hoya leaves and maintain a healthy Hoya plant with bright green leaves by making just a few changes in the lighting conditions, watering schedules, pot placements, and potting mixes.