Hoya kerrii, also known as Valentine Hoya or the sweetheart plant, is relatively easy to grow and care for because of its succulent-like qualities. But, despite being tough and drought-tolerant, there are certain circumstances that might cause its leaves to become curled and wrinkled.
Should you happen to notice your Hoya kerrii’s leaves curling, the most likely culprit would be low humidity or inappropriate watering. Your plant might also be struggling with too much sun exposure, pest infestation, plant stress, or temperature fluctuations. All of these factors are explained in detail below, so keep reading to find out what is bothering your precious plant!
Common reasons your Hoya kerrii’s leaves are curling
1. Root rot due to overwatering
Just like most houseplants, your Hoya kerrii can become a victim of root rot if overwatered. If you have let the soil remain waterlogged for too long, the plant’s roots will be deprived of oxygen, and will start to decompose and become a breeding ground for pathogens like fungi and bacteria.
So, what does an overwatered Hoya look like? How do you know if your plant is overwatered?
There are some tell-tale signs of an overwatered Hoya. If the leaves are curling and the soil looks wet, the first thing you should do is to check the roots. Carefully lift the plant from its pot and, if you see roots that are dark, mushy and foul-smelling, then overwatering is probably the culprit.
Keep in mind that root rot can also be caused by using the wrong pot or a soil mix with poor aeration. Pots that do not have enough drainage holes can lead to waterlogged soil, and this can be made worse if your soil is dense or compact, as that will also tend to hold more water. Standing water will cut off the oxygen supply that keeps the roots alive and healthy, and unfortunately, dead roots cannot be revived. If you do not act quickly, the rot will soon spread to the other, healthy roots and throughout the rest of the plant, leading to your Hoya’s early demise.
If you are a neglectful gardener, here is some good news: Hoya kerrii plants do not require tons of water to thrive and can survive dry spells up to a point, due to their succulent nature. You can let your Hoya’s soil dry out completely before the next watering, and the plant will not mind at all.
However, you can only allow the soil to stay completely dry up to a certain point. Excessive dryness, especially during summer, can cause stunted growth and leaf curling. If the soil is left dry for too long, your plant might not be able to recover.
3. Plant stress due to temperature fluctuations
Hoya kerrii thrives in temperatures between 60 and 80 degrees Fahrenheit; any temperatures that are too hot or too cold for the plant can cause stress. It is fairly easy to know when a Hoya is temperature stressed – its leaves will start to curl and turn yellow or brown.
Unfortunately, maintaining an ideal indoor climate can be challenging for most growers. Thus, it is not uncommon to see a Hoya kerrii struggling with temperature fluctuations at some point. If you notice your plant’s leaves curling and changing color, check your indoor temperatures and, if necessary, take measures to keep them within the plant’s comfort zone.
4. Lack of humidity
Your Hoya kerrii loves humidity. These succulent-like plants hail from tropical areas where the environment is quite humid, so if you want to speed your plant’s growth a bit, then keeping it in humid conditions will go a long way!
Although Hoyas can tolerate a degree of dry air, they do need at least 50 percent humidity for proper growth and propagation. Growing them indoors without sufficient humidity can cause several problems such as browning and curling of the leaves, stunted growth, and drooping.
5. Spider mite infestation
Pests like spider mites can significantly damage the leaves of your Hoya kerrii. These tiny, sap-sucking creatures dehydrate the plant by sucking the sap from its leaves, causing them to curl or wrinkle.
Spider mites are about one millimeter – or 1/32 of an inch – long, and look like tiny white or black spiders. In the early stages of infestation, it can be quite tricky to spot them on the leaves due to their minuscule size. You will probably only start seeing the tell-tale signs of the infestation once it has become large and the foliage damage is obvious.
6. Leaf burn due to direct sunlight exposure
Hoyas thrive in areas with medium to bright, indirect sunlight. However, they can also tolerate exposure to about two hours of direct sunlight per day. Thus, it should be perfectly fine to let your Hoya kerrii enjoy the morning or afternoon sunshine.
Keep in mind, though, that too much exposure to direct sunlight can be harmful to your plant’s leaves! The sun’s intense heat causes its transpiration rate to increase, which can burn and curl the leaves. Loss of moisture from the foliage is just one sign that your Hoya is struggling with oppressive heat. If you do not correct the issue, the prolonged sun exposure will eventually cause irreversible damage and could even kill your plant.
7. Transplant shock
Hoya kerriis do not generally need to be repotted frequently. These succulent-like plants actually prefer to be slightly root-bound, so it is best to leave them in their original container for years.
However, there are times when repotting is necessary. If you need to transfer your Hoya to a new pot and fresh soil mix, it is likely that its leaves will curl due to transplant stress. Do not worry – this curling should only last for a short time. Once the roots have re-established themselves and your plant has acclimatized to its new container, its leaves should bounce back to their normal, healthy shape!
How do you fix curling leaves?
Once you have identified the cause of your Hoya’s curling leaves, it should be relatively easy to return it to its usual shape and vigor. Here are some tips to help you fix the leaf curling issue:
1. Correct your watering habits
Because Hoyas behave a bit similarly to succulents, they are also especially vulnerable to root damage due to inappropriate watering habits. These plants are excellent at retaining water for extended periods, so they will likely survive under the care of neglectful gardeners.
However, if you want your plant to really flourish and grow beautifully, you need to avoid both underwatering or overwatering. Here are some useful tips you can follow:
- Water your plant only when the soil is dry.
- Feel the top layer of soil by inserting your finger about one to two inches deep. Water the plant if the soil feels dry, but if it is wet or moist, wait a bit longer before watering.
- Use a soil moisture meter for even more accurate moisture readings without getting your hands dirty.
- Use pots with sufficient drainage holes and an airy soil mix. This will prevent excess water from sitting at the bottom of your pot and save your plant from root rot.
2. Repot if necessary
As mentioned, frequent repotting will not benefit your Hoya, because these plants prefer to be slightly rootbound. It is usually better if they are left in their original pots for about three years, unless there are valid reasons to repot.
For example, if the roots are expanding and become very dense, then you might need to transplant your plant to a bigger container. Another possible scenario is when you want to save your plant from a fungal disease.
3. Proper lighting and temperature
Sunlight exposure and temperature are two of the biggest factors that affect plant growth. That means that if you want to keep your Hoya in tip-top shape, you need to provide appropriate indoor growing conditions year-round.
First, ensure that your plant receives sufficient sunlight daily. You can place it near an east- or north-facing window to receive enough light while avoiding the most intense heat of the sun. Hoyas can also tolerate direct sunlight, as long as you do not overdo it. Let the plant enjoy a maximum of two hours of direct sunlight and it should still be perfectly fine.
Second, protect your indoor plants from harsh weather and fluctuating temperatures. For example, during the winter months, keep your Hoya in a room with a mild and constant temperature. Avoid placing it near an open window or balcony where it would be exposed to cold drafts. Also keep it away from heating devices or air conditioners to prevent foliage damage.
Should your plant end up accidentally exposed to cold temperatures, move it right away to a room where it can warm up. Some of its leaves might curl, but your plant should recover quickly.
4. Invest in a humidifier
Humidifiers can be real plant-savers, especially during the seasons when the indoor air is most dry. To prevent your Hoya’s leaves from curling, install a humidifier in the room to maintain the ideal humidity for it.
Alternatively, you could also place your Hoya in a humid room, like the bathroom. Just keep in mind not to mist its leaves, because although it loves humid conditions, too much moisture can attract fungal pathogens and cause serious damage to the foliage.
5. Treat pest infestations promptly
There are many options available to treat a pest-infested plant. One of the most effective treatments is insecticidal soap. Simply mix about five tablespoons of soap per gallon of water and spray the solution on the leaves and stems.
Another option is neem oil. This natural pest repellent is extracted from the seeds of the neem tree. Because neem oil is made of organic ingredients, it is completely safe to use on your Hoya to eradicate the pests.
Creating a mix of dish soap and water might work, too! If your plant is infested with aphids or fungus gnats, this solution should help get rid of their eggs and larvae.
To get rid of spider mites, you can also use alcohol diluted with water. Mix one cup of alcohol with about 30 oz of water and put the solution in a spray bottle. Then spray the affected leaves, especially on the undersides where mites love to hide, and wipe them off using a clean cotton cloth or paper towel.
Although Hoya kerrii is a neglect-tolerant plant, there are some situations that will cause its leaves to curl and turn brown or yellow. These signs are generally indicators that your plant is struggling with an environmental stressor – this could range from incorrect watering to pest infestations.
Try to get to the bottom of this, because only once you have figured out the problem can you apply the appropriate fix to get your Hoya’s lovely leaves back in good shape!
Image: istockphoto.com / phollapat