Native to Southeast Asia, the Hoya Kerrii is easily recognized for its heart-shaped, succulent-like leaves. It’s no surprise why this species is nicknamed the Sweetheart Hoya. 🙂
Growing the Hoya Kerrii is easy, but you’ll need to understand its native environment to care for it well. It needs:
- Several hours of direct light; When kept indoors, a South-facing windowsill is ideal.
- To be almost completely dry before watering.
- A well-draining and airy potting mix.
Thankfully, the Hoya Kerrii is safe for children and pets. 🙂
Here’s everything you need to know to care for your Sweetheart Hoya.
But wait, can a single leaf Hoya Kerrii grow into a full plant?
While single leaf cuttings are popular around Valentine’s Day, these cuttings lack nodes. They, therefore, do not have the ability to grow into a full plant.
Plus, Hoya Kerriis are notoriously slow-growing, so you probably want to buy at least a small plant to start off with!
Caring for your Hoya Kerrii
Light
Hoya Kerriis need several hours of direct light a day. When kept as a houseplant, look for the sunniest spot in your home.
Southern-facing windowsills are ideal.
This is especially true for variegated versions of the Hoya Kerrii, as varieties lack chlorophyll in parts of their leaves.
As a result, you need to compensate for the lack of chlorophyll by providing higher levels of light.
If you don’t have much natural light in your home, consider using a grow light at 1,500-2,000 foot candles.
Water
Look at those thick leaves! Water is stored in your Sweetheart Hoya’s leaves to allow them to ensure dry spells.
As a result, they:
- have lower water requirements; and
- are susceptible to overwatering (which can lead to fungal diseases and root rot).
Let your plant dry out between waterings.
When the soil appears slightly cakey, water your plant. Don’t water unless the topsoil is dry.
When watering, give your plant a thorough soak. Water slowly and deeply, near the soil line.
Allow the entire root ball to be saturated, and excess water to escape from the drainage hole.
Signs of Overwatering and Underwatering
Puckered leaves mean your plant is underwatered!
On the other hand, yellow leaves commonly indicate an overwatered plant. (Here are some watering tips if you are a beginner.)
Humidity
Your plant comes from Southeast Asian rainforests, where humidity is naturally high.
This means that while your Hoya Kerrii can grow well in average room humidity, it grows even better when humidity is >50%.
If you want to give your plant a humidity boost, consider using a pebble tray, or grouping plants together (provided that they are still in a spot that has adequate sunlight).
However, the easiest way to increase humidity is to use a humidifier. Set to 60%, and that’s it! 🙂
Temperature
Lucky for you, average indoor temperatures are fine for your Hoya Kerrii.
Ideal temperatures are 60 to 80 degrees F (16 – 27 degrees F). Drops below 50 degrees F (10 degrees C) can damage your plant. At a minimum, it will cause your plant’s growth to slow even more!
As with many houseplants, keep away from air vents and drafts.
Flowering
If you are patient, you’ll notice flowers growing. These emerge as star-shaped clusters of white and pink flowers.
You’ll need to wait about 3 years before flowers start to form.
Sometimes we notice that the flowers can produce thick and dark sticky nectar. Just be careful of this as it may stain nearby furniture or cushions.
Why is my Hoya Kerrii not flowering?
If you’ve waited patiently for 3 years and your Hoya Kerrii still hasn’t bloomed, here are some common reasons why:
- Insufficient light. Hoya flowers need optimal growth conditions, so check that you have chosen the sunniest spot indoors, and bright but dappled light outdoors.
- Insufficient nutrients in the potting soil. Use a high-quality indoor potting mix – see the Soil section for details.
Also, to encourage blooming,
- Keep your plant slightly root-bound. A little snug in the pot is a good thing!
- Switch to a phosphorous-heavy fertilizer to support flowering.
- Do not dead-head the flower stalks (peduncles!). Your Hoya Kerrii “re-uses” old peduncles for new flowers. So, refrain from cutting these off.
Growth
When grown indoors, you can expect your Hoya Kerrii to reach a height of 13 feet (4 meters) long! Ours puts out a handful of new leaves every year.
Over time, you’ll see this evergreen vine climbing up on bamboo sticks and trellises, putting out new leaves as it develops. But it is a slow grower, taking several years to become a full-grown plant.
When it starts blooming, your plant typically doesn’t grow new leaves, but rather focuses its energy on developing flowers.
In about 3 years, you’ll be rewarded with clusters of star-shaped, pink and white flowers. However, these also have a dark, sticky sap that may stain items nearby, so be careful where you place it!
Soil or Growing Medium
Being an epiphytic (climbing) plant, your Hoya Kerrii does not appreciate its roots being held in heavy soils. Even worse, it hates being waterlogged.
So, you need to choose a chunky (airy) and well-draining mix. We like using:
- 2 parts high-quality indoor soil
- 1 part perlite
- 1 part orchid bark
Alternatively, you can also try LECA. LECA is amazing for Hoyas, reducing the risk of overwatering and providing maximum breathability for roots.
Here’s our guide on the Pros and Cons of LECA to see if this is a good fit for you.
Fertilizer
Being a light feeder, your Hoya Kerrii doesn’t need much.
Use a nutritionally complete, liquid houseplant fertilizer once a month at half strength during the active growing season (Spring and Summer).
That’s it. Don’t do more. If you give it too much fertilizer, you’ll damage its roots.
Climbing Support
Being an epiphyte, your Hoya Kerrii loves to climb. Encourage its natural growth habit by giving it a climbing support.
This helps your plant grow faster and healthier. (You can read why in this article about moss poles, but applies generally to other climbing supports too.)
Our favorite for this Sweetheart Hoya is a U-shaped bamboo stake.
Repotting
As with most small vines, this Hoya Kerrii enjoys being snug in its pot. Plus, your plant is a slow-grower, so repotting is not a frequent occurrence.
The most obvious sign that your plant needs repotting is when roots peek out from the drainage hole or swirl above the soil’s surface.
Spring is the best time to repot.
Here’s how:
- Water your plant the day before repotting; this reduces transport shock.
- Gently place your plant on its side.
- Use your fingers to tease away compacted soil.
- Remove your plant from its pot, being careful not to damage its roots.
- Use a new pot that is 2 inches larger than the original (any larger, and there is too much unused soil that holds moisture, leading to overwatering).
- Use fresh soil as nutrients deplete over time.
- Don’t water your plant until a week after repotting.
Toxicity
Thankfully, your Hoya Kerrii is non-toxic to pets and animals. Like all Hoyas, however, they do produce a milky sap that can be irritating for sensitive skin.
So, use gardening gloves when pruning or propagating.
Propagation
Propagating a Hoya Kerrii is easy, and has a high success rate. Our favorite way is through stem cuttings.
Propagation through stem cuttings
Before getting started, we always like to sterilize our garden shears by dipping these in 70% isopropyl solution. This prevents cross-infection.
- Identify a healthy stem around 4-6 inches (10-15 cm) long that has at least 1 node and 3 leaves. Best to find a stem with a few aerial roots too, this allows your cutting to root more quickly 🙂
- Using clean garden shears, cut off the identified portion of stem, just below the node.
- Remove any leaves from the bottom half of the stem only.
- Prepare a jar of room-temperature water.
- Place the stem cutting in the jar, ensuring that no leaves are submerged.
- Place in a warm spot with plenty of indirect light. If you have a humidifier, set it at 70%.
- Replace with fresh water every few days, to prevent the water from turning murky.
- In a couple of weeks, you’ll find little roots growing from the nodes, and from the cut end of the plant.
- Once the roots are about 1 inch (2.5cm) long, plant the cuttings in evenly-moist potting mix.
- Treat as you would any other Hoya Kerrii.
Pruning
Your plant puts out long vines, so you may need to prune off vines occasionally. This also helps encourages bushy growth – which in our opinion, makes your plant look gorgeous and full 🙂
Remember to use clean garden shears (we use 70% isopropyl solution to sterilize our tools), and cut in a downward slant, just above the node.
Be careful not to cut off peduncles (flower spurs), as they re-bloom from the same spurs season after season.
Common Pests and Diseases
Thankfully, your plant is relatively pest-resistant. If you do have an occasional infestation, the most likely problem is mealybugs.
Other than mealybugs, diseases arising from an overwatered plant are common. These are root rot and other fungal diseases.
Root Rot
Root rot is a headache for many gardeners. It results from overwatering your plant. If you see your Hoya Kerrii’s leaves turning yellow, chances overwatering may be the cause. Check if the soil is damp to confirm.
If your plant is only slightly overwatered, relocate it outdoors, where excess water can evaporate quickly.
However, for more severe cases, you’ll need to dislodge the plant from its pot and inspect the roots.
Healthy roots are thick and white, while brown or black roots are signs of root rot. Roots are unable to breathe as they are drowned out by water.
As a result, they started to decay.
To save your plant, you’ll need to use sterilized shears to snip off the infected roots, then repot them in fresh soil.
Consult our step-by-step guide for details!
Botrytis blight (Botrytis cinerea)
Botrytis also known as grey mold, is another common fungal disease spread by wind or water. You can identify this fungus by lesions or streaks on leaves that turn fuzzy and grey over time. In addition, fungi feed on nutrition from the plant causing it to droop or yellow.
Here’s how to save your infected plant:
- First, gather and destroy fallen damaged leaves and dispose of them securely. Growth on affected leaves can re-infect other parts of the plant or new healthy plants it comes into contact with.
- Isolate your plant from other plants to prevent contamination.
- Trim off any damaged leaves, again carefully disposing of them. Make sure to sterilize your garden shears using 70% isopropyl before and after use.
- Apply a fungicide that contains chlorothalonil to contain the spread of the infection. Chlorothalonil is an effective broad-spectrum pesticide.
Mealybugs
Mealybugs are a common sap-sucking pest that infects household plants. If you spot a mealybug,
- Thoroughly inspect all your plants, including under the leaves and at leaf axils. These bugs love to hide in hard-to-reach corners!
- Quarantine any infected plants away from all other plants to prevent cross-infection.
- Using sterilized garden shears, trim off any visibly damaged or heavily-infested parts of the stems and leaves. We use 70% isopropyl solution to sterilize our gardening tools; this is important as cross-contamination is a common cause of spread.
- Apply an Insecticidal Soap spray to the remaining stems and leaves. Reapply as necessary and as the instructions dictate until you see that the infestation has been eradicated.
- Apply a neem oil solution to all other plants as a preventative measure against infestation. Neem oil disrupts the growth of larvae and prevents mealybugs from feeding, growing and reproducing.
For information on how to identify mealybugs and a step-by-step guide on killing them off, read our guide.
Variegated versions
The Variegated versions of the Hoya Kerrii are highly sought after (as with most variegated plants!).
They require the same care conditions as the all-green Hoya Kerrii with the exception of light.
Light requirements are higher for variegated versions. The more variegated, the more light it requires.
Hoya Kerrii ‘Albomarginata‘
The Hoya Kerrii Albomarginata has green heart-shaped leaves with yellow margins. Margins are usually not clean and straight, rather have colors that appear to “bleed” into each other at the edges.
Hoya Kerrii Splash
The Hoya Kerrii Splash features irregular silver speckles throughout the green leaf.
Hoya Kerrii Picta (Hoya Kerrii ‘reverse variegata’)
The Hoya Kerrii Picta, has the same heart-shaped leaves, but with yellow centers and green margins. There is usually some overlap between the different colors. The leaf may have 2-4 shades of greens and yellows in total.
Troubleshooting
Yellow Leaves
Yellow leaves are most commonly a sign of an overwatered Hoya. Check the soil moisture with your fingers to confirm.
Curling Leaves
Curling leaves are a sign of improper watering (either too much water or too little) or temperature shock.
Remember that your plant has lower water requirements due to its succulent-like leaves that hold water. At the same time, don’t wait until the leaves are puckered before watering.
Keep temperatures between 60 to 80 degrees F (16 – 27 degrees F). You don’t want to deviate too much on the higher or lower end of the spectrum.
Slow Growth
Slow growth is normal for this plant. It is naturally a slow-grower, even under optimal conditions!
But one thing that can slow growth even further is not having enough light and warmth. Ensure you place your plant in Southern-facing windows, or use a grow light.
Keeping your plant indoors, away from cold chills also helps. Your Hoya Kerrii is not cold-hardy.
Frequently Asked Questions
Where can I buy a Sweetheart Hoya?
We don’t recommend you wait until Valentine’s Day to buy a Sweetheart Hoya. Take matters into your own hands and buy one at a local gardening center, or online through Etsy. 🙂
Other Hoyas we Love
- Hoya Rangsan – a variegated Hoya with yellow, sweetly fragranced flowers
- Hoya Nummularioides
- Hoya Heuschkeliana, a trailing Hoya with succulent-like fleshy leaves and yellow or pink flowers
- Hoya Carnosa Compacta, the Hindu Rope Plant
- Hoya Imbricata
- Hoya Pubicalyx
Wrapping Up
The Hoya Kerrii is an easy plant to take care of, as long as you have a little patience. The most important parts of care are:
- Several hours of direct light when kept indoors
- A well-draining potting mix (we like using perlite + orchid bark to improve drainage)
- Letting your plant dry out between waterings
- Average room temperatures
- Humidity >50% is optimal
- Light fertilizing, once a month at half strength using a high-quality houseplant fertilizer
- Flowers produce a dark sticky sap that may damage furniture or cushions nearby!
On a Hoya kick? Check out the easy-going Hoya Bella next!
Deborah is a plant enthusiast and founder of Gardening Collective.