Better known as the Wax Plant, Hoyas are beautiful yet picky succulents that grow naturally in tropical regions of Asia and Australia. With a wide variety of species under its umbrella, the Hoya genus is best known for the Hoya Kerrii Heart, a trailing plant with round, heart-shaped leaves. Grown either as a vine or as a single leaf, the Hoya Kerrii Heart is a beautiful succulent, but just like the rest of its fellow wax plants, the Kerrii Heart is finicky. If something’s wrong, its leaves will likely turn yellow to show their distress.
These are the most common causes of Kerri Hearts yellowing and some solutions:
Succulents are especially susceptible to overwatering, and the Hoya Kerrii Heart is no different. Overwatered Hoya leaves will appear yellow and swollen and may be squishy when you touch them. One of the biggest causes of yellowing leaves in Hoya plants is too much water; there are a few ways to remedy this. First, only water your Hoya when the soil is completely dry to the touch. To test soil moisture, stick a wooden chopstick (or your finger) as far down into the soil as you can. Like testing a cake, your chopstick should come out clean, with little dirt on it.
Overwatered Hoya leaves will appear yellow and swollen and may be squishy when you touch them.
Photo via botanicalgarden.ubc.ca
Even the best watering routine can’t stop a Hoya from struggling from poor drainage. If your soil retains too much water, your Kerrii Heart will start to feel the effects of overwatering. The best soil for wax plants is modified succulent soil. Succulent or cactus potting mixes are relatively nutrient-poor, but they’re amazing for drainage. To modify your soil mix, add a little compost to the mix.
Pests and Disease
Poor drainage and overwatering can also eventually lead to your Hoya contracting pest infestations or diseases. Fungal gnats, mealybugs, sooty mold, and root rot are the most common complications that may arise when this normally pest-resistant plant gets too much water. If your Hoya’s leaves start to yellow, consider checking your plant for signs of infection or infestation.
Mealybugs is one of the most common complications that may arise when this normally pest-resistant plant gets too much water.
Photo by Frederic Cerez
Ironically, underwatering can also cause your Hoya’s leaves to turn yellow. Fortunately, there’s a difference between underwatered yellow leaves and overwatered yellow leaves. As we’ve mentioned before, overwatered leaves tend to appear swollen and squishy, while underwatered leaves will turn yellow or brown and start to wrinkle. They may also fall off of your plant.
If your Hoya is underwatered, give it a drink– sticking to a frequent watering schedule should help keep your Hoya hydrated!
Too Much Light
If your Kerrii Heart gets too much light, its leaves will start to yellow. All succulents prefer bright, indirect sunlight, and too much direct sun will burn the leaves, causing them to turn yellow or brown. When placing your Kerrii Heart somewhere in your home, consider putting it near an east or south-facing window to it’ll receive plenty of sunlight, but not harsh, afternoon sun.
Getting too much light also makes Hoya leaves turn to yellow.
Photo by tse Pui Lung
As tropical plants, Hoya don't like cold temperatures. They aren’t frost-hardy and will start to yellow if the air around them is too cold (below 50 degrees Fahrenheit). Indoors, check for any potential drafts around your Hoya. While cold drafts won’t kill the plant, they can still shock your Hoya and cause its leaves to yellow.
Just like with sunlight, you may have to relocate your Hoya to ensure it doesn’t get too chilly. Try to avoid placing it near drafty windows or air conditioning units to ensure it doesn’t get too cold.
Unlike most succulents, the Hoya Kerrii Heart and other members of its genus need more nutrients than the usual succulent. Fertilizing your Hoya regularly (about once a month) with a nutrient-balanced fertilizer solution is the best way to remedy any sort of deficiency. During the plant’s growing season, add a diluted 50/50 mixture of water-soluble fertilizer to your watering schedule. This won’t cure any yellowed leaves but will prevent new ones from yellowing and encourage new growth.
Unlike most succulents, the Hoya Kerrii Heart and other members of its genus need more nutrients.
It’s Been Moved
The bane of all picky plants is change. If you’ve checked your Hoya Kerrii Heart for all other problems and its leaves are still yellow, look back to the last time you moved it. Did the indoor environment change at all? Did you repot your Hoya recently? Sometimes, your Hoya’s leaves turn yellow simply because it’s stressed from an environmental change. Whether you’ve moved house or just relocated the plant, it’s common for a Hoya to show signs of stress as it acclimates to its new environment. As long as you keep caring for your Hoya like you normally would, it’ll adjust and should be fine.